There are quite a lot of threads on this site covering this question. Basically: Canon cameras seem to overheat less than Nikon and have a slightly better Live View for connection with your computer.
Get old manual lenses to use for stop motion. There's a good video on Youtube on using vintage lenses for stop motion. Also get a mains adapter - I have found the generic type quite OK.
My main camera is a Canon 600d, not made any more. This is the same type that was used to shoot Peter and the Wolf and doubtless many other stop motion films. New equivalent is the 750d, I think.
If you will be using Dragonframe, check on their website for compatible cameras, most DSLRs are but do make sure.
I use a Canon 40d and a Canon 7d, but models change all the time and neither of those is made any more. You can go with the entry-level DSLRs rather than the mid-range models. I use manual Nikon or Olympus lenses, with adapters. I also use an AC power adapter, a genuine one for the 40d and a cheap under-$20 one with the 7d.
All the Canon EOS DSLRs work well with frame grabbing software. So do Nikons, but the resolution of the live view is a little better on the Canons. If you go to Dragonframe's website, they list the compatible cameras and give some details on resolution and how to connect them. https://www.dragonframe.com/camera-support/
In terms of cost, you might be up for:
Camera - for example, Canon EOS 750d (Rebel T6i in USA) body only - US $549 on Amazon. (If you get the standard package with the 18-55mm kit lens, you will use that for general photography but not for animating.)
Used manual Nikkor 55mm "Micro" (macro, will focus up close) $?
Used manual Nikkor 28mm wide angle or 24mm wide angle - $? 28mm and 55mm are the two I use the most. Manual means you can set the aperture and focus on the lens barrel, not have it electronically controlled (and changed) by the camera's little pea brain. Using another brand of lens with adapter also means the lens stays stopped down to the f-stop you set, all the time, instead of opening up between shots for a brighter view and trying to stop down accurately when you take the shot. This keeps exposures steady.
2 Nikon-to-Canon lens adapters, simple with no glass or electronics, about $12 - $17 each. ( https://www.ebay.com/itm/Lens-Adapter-For-Nikon-F-To-Canon-EOS-7D-M... )
One AC power adapter, genuine Canon (expensive) or cheap Chinese, under $20.
A tripod. I use a heavy Foba that cost $300 second hand, (about $1500 new) and a lighter one that I bought for $8 from a charity shop. Both work. I also use a Manfrotto 410 Jr geared head on the big tripod for smooth animated camera pans and tilts, but it's not essential.
Framegrabbing software - Dragonframe full version, US $305.
This sort of kit will let you do professional level work if you want to, so you won't need to upgrade as your animation gets better.
The absolute cheapest option, and not bad for learning, is to simply use a smart phone or tablet that you already have, with the free version of Stop Motion Studio or other capture software. You can get little mounts that grip the phone or tablet and attach to a standard camera tripod. Nearly all will shoot 1920 x 1080 HD. You are somewhat limited to the standard wide angle lens view, and they shoot video rather than the larger, cleaner high quality stills that the DSLR cameras capture, but you can do all the basics like seeing the live view and clicking back to compare with the frames you have already taken (or onionskinning if you prefer that method).