3Pro

Cheapest + most effective is a CR Box/Corsi Rosenthal box.  So you buy a cheap box fan (30ish bucks) + a set of 4 filters (such as filtrete 1900 - around 60ish) so for under 100 bucks or so....you get a very powerful air purifier with around 400 CFM power.  Levoits are excellent and I still have two core 300s on the corners of my living room..m but 1 core 300 is not enough power. ( I now have 8 purifers for a 1 bedroom apt as I need excellent coverage since I have an old carpet I inherited here with 5x kids of mold on an test.). But my air is crisp and clean now thankfully.  So you aren't going to have excellent coverage with 1 90 dollar Core 300.  You might need 3-4 of them for excellent.  2-3 might be "good" coverage, perhaps. (Or just one of they larger units like the core 600 or Everest Air but those are around 350-390 I think)  Point is the Core 300s have 155CFM so great for a small or medium room.  For proper coverage, given allergies and such, you will need likely a lot more than that.  As general CADR numbers are based off 1 air change per hour I think. But you want 4x air changes per hour for excellent coverage.  (Every 15 mins.) So a CR box will give you around 400 CFM m, for 90ish bucks, about the same as a 350 dollar bigger Levoit unit.   So I would suggest tape together a set of filters to a box fan....while you save up if you want a bigger Levoit. But that is cheapest way to get very good coverage.  Prob 1 CR box + 1 core 300 in bedroom.  But keep adding units as needed.  Also this doesn't mention sound.  For more quiet units those are more expensive, like a 1,000 Dyson that doesn't even move much air.   Or you could get a bigger pricier unit and run it on low, to still get decent CFM.  But you won't get both high CFM, and very quiet, for the price point you mention.  Although I don't find box fans loud pet se, and my purifiers to me are quiet, all running on high.  I have gotten used to it and actually like the background noise and don't even notice it.   (As compared to when I got my first Levoit Core 300 and noticed it more.)  So you will probably just have to get used to the sound, as that can just happen naturally after a while.   But again, sound is subjective so idk exactly what is "loud" for you.   But fans are in purifiers and all fans make at least a little noise pretty much.  So it's a trade off but vastly worth it...for having better quality air.   Other good brands are Winix and Coway, also as loud/quiet (depending on ones opinion) as Levoits.  They all perform pretty close and top 3 in recent testing for both performance + decibels.   So a combination of 1 CR box + 1 affordable unit will probably get you a decent amount of base coverage.  Then add another unit/upgrade from CR Box later if needed.  (You can also still keep using the CR Box for even better coverage or even putting 1 filter behind a box fan when upright normally...can also add to coverage and save  space.) 

I missed the last part of your post about considering a 350 range unit at top end.  So the Core 600 is I think 269 on levoit.com or around 300 maybe on amazon. So I would get the best unit you can afford...and then add a CR box/other unit when you can afford another. I am not a expert in dimensions, but using the calculator on the wiki page w 1,000 feet and 8 foot ceilings, and a target goal of 4 ach (air exchanges per hour) gives I think 466 CFM needed. Now they page actually shows 4 air changes per hour on the cusp between "minimum" (3-4ach) and "good" (4-5 ach)  and it says excellent is actually 6 ach.  (You would need 733CFM for that.) So the Levoit core 600 gives like 391-430 depending on dust/smoke/dander etc.  So you would be at at least adequate protection....with just a core 600, and on the cusp of "good".  So basically in your living room, best the unit, you will have very good protection. And in a bedroom or further away room still adequate.  So that would likely be a very good unit to get to start.  And whether you want to add a CR box or a smaller purifier in bedroom for more coverage later...you can find out.  (The Core 600 + CR box gets you to 800 range CFM units running on high, so that gets you excellent. Core 600+ a core 300 in bedroom gets you almost 600 CFM, so very good coverage that way too.) Remember, a bigger unit you can lower/more units run lower, will be quieter but get you equal CFM.  So the larger unit is the best way to go by all accounts.  And just add another later if you want/need excellent etc. 

Not from any large corporations, I don't think.  But there are some smaller companies that make them in a more attractive housing, (so more palatable to the wife probably.).  Such as cleanairkits.com, Nukit, Air Fanta etc.   You could also customize it and make your own, however you want.  (Or get someone to make one for you as some people that post here make the housings.  You can just go with a clean white perhaps, to better "look" like a normal air purifier.    But check those sites. Also...why not just get a regular air purifier ?   As they both do the same things generally, both get let dander for instance, they just vary by how they do it slightly.    https://www.cleanairkits.com/ https://air-fanta.com/products/airfanta-3pro https://cybernightmarket.com/products/the-nukit-tempest-euro-pc-fan-air-purifier-kit

Yes, I am aware and as per Google (via IQAIr source + others)  "Yes, ozone produced by air purifiers can be harmful even at levels considered "safe" or compliant with regulations. Ozone is a toxic, reactive gas that irritates the lungs and respiratory system, causing coughing, chest pain, and worsening conditions like asthma, regardless of whether it is generated intentionally or by ionizers.  U.S. Environmental Protection Agency (.gov) U.S. Environmental Protection Agency (.gov)  +3 Why Ozone is Harmful Even at "Safe" Levels: No Truly Safe Level: Studies indicate that even small increases in ozone can cause significant respiratory discomfort, decreased lung function, and increased mortality, especially for sensitive groups like children, the elderly, and those with respiratory diseases." So yes the number is low, but it is not 0.  What is safe for "most" is not safe for every individual (and animal).  For instance I had a medical issue that is 1 in 4,000.  So even if 95% are fine...5% may not be.  (Or even 1 in a 1,000.). So why take the chance if someone has never owned an ionizing unit before ?  The bare minimum for a first time unit...is to at least have an on/off ability which blue air just does not have.  It might be a fine choice for even most people, but it won't be a good choice for everyone.  It's a risk for a first timer as they just wont know how they react to it.  As well consider that people might have multiple units running....and these tests are only done on 1 unit.  So if you have like 3,4,5 units all employing even a "safe" level of ozone...then you may be then getting above a safe level at that point.  As you will then be getting 3,4,5x as much ozone dose if you have multiple units running. It. As well the size of space also matters, as in one study they put a unit in a small bathroom...a unit which has the "safe" ozone levels under 50ppm or whichever metric...and even that created over the threshold to an unsafe level and what would be a level 2 safety smog alert.  (Not how the unit is intended to be used they acknowledge, but undoubtedly some people will be running too big or too many units ..and getting to possibly unsafe levels..even if each unit individually is tested "safe".) As well some say that no amount of ozone indoors is safe to breathe. (As IQAir seems to be saying and that "safe" level keeps going down further and further...so we really don't know what is truly safe, and certainly safe for most...is not safe for every person.). Especially for their first unit.  It's just a flaw with BlueAir even if their units are good quality.   "Underwriters Laboratory’s UL Standard 867 requires household air purifiers to produce no more than 50 parts per billion (ppb) of ozone. However, even this level is not safe for humans to breathe." https://www.iqair.com/newsroom/are-you-polluting-your-home-ozone Note: I use a different brand one with ionizer, but I toggle it off sometimes. I like the function, so that works for me. But for a first time buyer...it must have toggle on/off otherwise it's a risk that they may not like the unit, or maybe even detrimental to thier health/animals etc.