For your situation I'd suggest a used ruger GP100 or the SP101 as a close second. They're stout revolvers so you can get heavy 180 or 200 grain bullets from specialty ammo makers like buffalo bore. That would probably penetrate deep into a thick-skinned gator and hopefully do enough damage on the way through to stop it. (I'm not too familiar with gators so I don't know for sure.)
Even a used one might run you a little more than $400 but it would be well worth it. There are no cheaper revolvers on the market that I would recommend, especially for heavy buffalo bore ammo or similar heavy loads.
im going to be honest i have considered both a hi-point and a taurus despite the horrible things people say. I figure that like anything you should always inspect and test what you buy, i also dont think i will feel too bad if i lost either in comparison to a ruger or a smith. Since you brought up taurus revolvers how does rossi compare to them?
Taurus is a crap shoot and Rossi is Taurus' budget brand. I wouldn't buy either. I had a Taurus and it was junk and I had a buddy that got a Rossi for $50 (that should tell you something right there) and it made the Taurus look good by comparison.