Celsius XXL 20°F

Certain colors of the Teton Celsius xxl is on sale for $65. I bought a 20° one recently and its great!

Really any bag rated for 15 to 20 degrees lower than what's forecasted. Fahrenheit by the way. If it goes down to 20 don't expect to be comfortable in a bag rated only for 20. For at or below freezing temps you want a bag rated for 15 to 0.  Teton has some sales going on right now making some great bags under $90. And some closer to $50. I have the celsius XXL 20 and it did great for 40 degree nights. And it's big enough to roll on my side inside of.  Also you will want a mat or something under you otherwise the ground will steal your heat. Harbour freight has cheap moving blankets you can fold up and put under you to help if you're in a pinch. 

Teton Celcius XXL, there is so much room in there. I'm a big dude and I roll in it easy.

Do you NEED -35F? If you do I would buy a proper brand sleeping bag, and not mid tier. -35f is nothing to mess around with. And I would get a mummy bag in that case, and I do not like mummy bags. Teton themselves are a decent brand, but like most mid tier brands their advertised rating is not for comfort but survival, and usually a\~10 degree fudge factor. Similar to "on paper vs reality". Square bags also do not keep in heat well compared to a mummy. If you need sub freezing I would do more research. Things like how they insulate the zipper can make of break a decent night of sleep. I have a +20 degree Teton synthetic rectangle, it's the XXL size. And although it's super nice for the price and keeps me warm I noticed around 38-40 degrees if there's any wind it gets into the sleeping bag through the zipper. Not saying this will do the same, just an example.

Ive used their 20 degree bags in mid 30s to high 20s before and it did well enough, I was still able to comfortably sleep even though it started to push that comfort rating. I'd trust the teton brand to be accurate for their temp guidelines, heavy af though.

I have a Teton 20° bag and I put a down puffer blanket in the bottom, under my legs, and around and over my feet, and overtop my legs, *inside* the sleeping bag. Then I wrap a second puffer blanket overtop on the outside. This, good wool socks, and sleeping in smartwool base layers, and I was toasty down into the low 20s.

Second the Teton Celsius XXL! I grabbed one a couple years back for a week-long trip and it was a game changer for both warmth and comfort. I’m a side sleeper too and being able to move around inside the bag made sleeping way easier than those tight mummy bags.

I feel your pain, brother. i'm 6'9" and in my 50's. Sleeping bag: Teton XXL celsius is a winner Cot: Teton sports outfitter xxl cot and Pad: while expensive will give you a GREAT nights sleep I find I have a lot less tolerance for sleeping on the ground on a sleeping pad. It's really not all that comfortable and getting up and down is a pain in the butt.