I’m looking to to start working out and I’d like to buy a treadmill. I’ve already got a bench and some weights.

I don’t need anything super expensive or loaded with tech, and something used would be ideal. What brands or models should I be looking at or which ones should I stay away from? I currently weigh around 235.

I got lucky and found a used technogym excite 1000 for $700.  It’s an awesome treadmill, most used ones go for over $2k

Cybex and life fitness make good treadmills as well

What you're looking for is an older, used model that was on a gym or something. Basically a commercial or semi commercial model.

A "cheap" new one won't be able to withstand much actual running by a person 70 lbs lighter than you. As Boris the Blade said, "heavy is good, heavy is reliable".
Nothing foldable.

Landice and Sole are a couple examples of good brands.

Sole F63 is beyond excellent.

Pretty much this. If you buy an entry level treadmill, even new, it WILL break.

I’ve been looking at the f63 and f80. I think I I’m going to snags a f63 that’s somewhat local.

Check the used market.  Wasn't too long ago a bunch of people got put on lockdown in their houses and the government was sending them a bunch of money to waste.  A lot of them got all antsy and spent it on exercise equipment even though they've never exercised a day in their lives.

One of my renters was one of those people.  He got a really expensive treatmill and used it about twice.  When I sold the house and he had to move out, he just said fuckit and left the treadmill.  It wasn't worth his effort to move it.  I tossed it in the truck and let my mom have it.

As someone who buys, sells, refurbs and services this stuff, I highly recommend a sued commercial unit over a new residential unit.  Life Fitness, Precor, maybe TRUE ... They will run better and last for many, many years if properly maintained.  I currently have 3,700 hours on the Life Fitness unit I bought used from a gym in NYC.  You can probably expect to pay around $1,500 for a refurbished unit w/ a 1-year warranty for parts/labor.  You can get a used unit that has not been refurbished for less though.  Just look for something that has been well-maintained.  Moving down the list .... Landice is not on the same level, but they are generally good machines.  SOLE is better than Pro-Form, NordicTrack, etc., but it's residential and not made especially well - just better than the really low-end models.