Welcome. I'm a crossbow hunter. Have been for a long time. I'm not injured...I just like it. I'm just going to spout on about a lot of things to think about and then I'll just give you a few actual bows to consider.
The things people usually compare with xbows are:
4. Width (axle to axle / cocked and un-cocked)
My opinion is speed isn't really all that important. I mean, it is, but almost all crossbows shoot well above 300 FPS so the differences aren't really very impact-full (especially if your shooting 40 yards and in).
The thing about a crossbow is that, for all of its advantages, it is pretty unwieldy...especially in a tree-stand. Not all of your shots are going to be nice sitting shots with a gun rest in front of you. The bigger (and wider) and heavier your bow is, the harder it's going to be to take those shots on from the other side of the tree, kneeling and off-hand, etc.
So, for me (again this is just MY OPINION), I primarily look for the shortest width first. I am most concerned about the UNCOCKED width. The reason? Even though the crossbow will be cocked the whole time you are in the stand, you'll need to make sure when you're taking that shot, that the limbs can fully release w/o hitting anything (this is important, you can be thrown from the tree if the limbs hit something). For this reason I stay away from re-curve type crossbows. They are too wide in my opinion. However, some like them (easier maintenance and longevity are some areas they excel at).
Second is weight. I like them as light as they can reasonably be. Even a pound can make a big difference sitting all day in a stand when you don't have a rest.
Length isn't a big concern for me because that doesn't really impact maneuverability. And all else being equal, I like a fast bow...but like I said, speed is secondary to width and weight.
Another thing to think about is reverse draw vs. standard. The reverse draw crossbows can be pretty thin...but I still prefer standard because (all else being equal) they are a little lighter. Another advantage of reverse draw is they are much better balanced. It's easier to shoot off hand with them. But one of the things I don't like is it's a little harder to shoot around a tree. I sometimes set up purposely facing the tree. With a standard, I can just lean the frame against the tree and the limbs will be on the side I'm shooting towards. They can clear the tree easily and I don't have to worry about the release. With the reverse draw you have to make sure you have a few more inches and I just hate thinking about stuff while I"m taking the shot..I like to stay solely focused. Note: A LOT OF GUYS WILL DISAGREE WITH WHAT I JUST SAID ABOUT REVERSE DRAW. They are getting more and more popular. Decide for yourself.
Another thing to think about is cocking. I always have a crank cocker installed. I can cock by hand or using a pull type rope cocker, but the installed crank cocker keeps the sting positioned exactly right so it should be more accurate a shot....so in my opinion it's worth the extra money.
Some bows can not uncock w/o shooting a bolt. This isn't a big deal to me. I just keep a crappy bolt in my truck with a field point and shoot it into the ground to uncock it. Some guys really think the ability to un-cock is important so think about that too.
In terms of actual bows. Barnett has a whole range of good cheaper bows. I owned a Ghost 350 and I liked it. I later sold it for a 10 point. 10 Point is a great brand with tons of customer loyalty. I own a 10 point shadow ultra light and love it. The 10 point is more accurate than the Barnett but a heck of a lot more money.
Speed guys and reverse draw guys seem to love the Scorpyd.
Hope this helps. Whatever bow you buy, practice from a tree stand before season. It's a lot different than shooting for a chair in your backyard. And keep your shots close. The xbow is not a gun even though it may look like one!
Shoot Straight and enjoy!