The Canon T2i was the top of the "Rebel" series line, in it's day. Outside N. America, it's known as an EOS 550D. It's a nine year old model, so probably isn't supported by Canon any longer (repairs, if ever needed, might be possible with an independent shop).
It's 18MP with a simple, 9-point AF system (one higher performance "dual axis" AF point, at the center of the array), and can take 4 shots per second in continuous shooting mode.
For comparison, the Canon T7i (800D) is the current top of the Rebel line (although the EOS 77D actually has very similar specs and might be considered a notch higher). The T7i is 24MP with a more advanced, 45-point AF system (all "dual axis" type) that's able to focus in lower light conditions and with more lens/teleconverter combinations. The T7i can shoot at 6 frames per second.
The T7i also has an articulated Touch Screen LCD on the back. It tilts and rotates to be able to view it from different angles or even from the front of the camera (i.e., "selfie" or "blogger" mode). The T2i's screen is fixed and isn't Touch-enabled. The T7i also has Canon's "Dual Pixel Auto Focus" (DPAF) in Live View mode and when shooting video (i.e., when the rear screen is used for composition, focusing, etc.... instead of the viewfinder). DPAF is a form of "phase detection" autofocus that's MUCH faster than the contrast detection autofocus used in the T2i and other cameras of that age.
There's nothing at all "wrong" with T2i... it's just an older Rebel series model. Since they are no longer available new, you'll need to shop used. It may be possible to check how many "shutter actuations" a used camera has seen (sort of like mileage on a car). Canon predicts cameras at this level will be good for about 75,000 "clicks"... This is merely an estimate, an average life expectancy across all copies of any given model, and not a guarantee by any means. But, it might be useful to know how much a camera has been used. There are apps that can "read" how many clicks some Canon cameras have seen, which might give you a rough idea how much "life" is left in it. I'd try to get that info, if at all possible.
Some have commented, and I agree, that lenses are more important than the camera.
T2i would have normally been sold with EF-S 18-55mm f/3.5-5.6 IS "II" or EF-S 18-55mm f/3.5-5.6 IS "STM" lens... the latter has considerably faster and quieter auto focus. Another difference is that the STM lens' front barrel doesn't rotate when the lens is focused. The II's barrel
does rotate, which can be frustrating when trying to work with a filter like a Circular Polarizer, which changes effect when it's rotated. Theses lenses are somewhat plasticky. They are inexpensive "kit" lenses, after all. But they are generally capable of making nice images. (Note: There have actually been six different versions of Canon EF-S 18-55mm lens... those two are just the most likely ones to have been originally fitted to a T2i).
These cameras have also often been offered in a two-lens kit with the 18-55mm and a second, telephoto zoom lens. Most commonly that would have been an EF-S 55-250mm IS "II" or EF-S 55-250mm IS "STM".... where the latter is preferable for some of the same reasons as the 18-55mm STM lens. Another, lower priced lens sometimes included in the kit is the Canon EF 75-300mm f/4-5.6 "III". Avoid this lens.... it's simply not very good... slow, noisy autofocus ("micro motor")... lacks Image Stabilization... has pretty poor image quality. The EF-S 55-250mm IS STM is a much better lens in all respects.
Of course, buying used it's hard to say what lenses might be included with a used camera, if any at all. Often people have added a lens or replaced a kit lens with something better or more suited to what they do. They might even have bought the camera without a lens and bought a third party (such as Sigma, Tamron, Tokina, etc.) lens to use with it. You'll have to carefully research any lenses that you might be offered. There's a lot of info online.
Online there appears to be a wide range of prices for used T2i. Be careful. I see "refurbished" advertised at a number of stores, but what does that mean? Is it any better than just plain "used"? Actual "factory refurbished" Canon cameras have only been sold directly from Canon's own website for some years now. Not in stores. Canon sold out of refurb'd T2i long ago. Here's a link to the other, most similar models currently available refurb'd from Canon:
https://shop.usa.canon.com/shop/en/catalog/cameras/refurbished-eos-interchangeable-lens-cameras#facet:-810369798332555568,-810369798332821019810110832837650,-8103697983328210198101108328455105,-8103697983328210198101108328454115,-8103697983328210198101108328454105,-8103697983328210198101108328453105,-8103697983328210198101108328451105,-810765808345673240494654120329911411111241&productBeginIndex:0&orderBy:11&pageView:grid&pageSize:72& Note that not all those cameras are currently available. Stock often comes and goes quickly there. So you may have to wait for a particular model you're seeking. And, when it does pop up, you might need to move quickly! A nice thing about Canon refurbished is that they have the same warranty as new. Buying used from a dealer often comes with at least a 90 day "store warranty", too. Buying used from a private party may cost less, but generally means no warranty at all.