Re: Best .22lr bang for the buck?
Well, a lot of that depends on what sort of action you're looking for, how close to your target goal of <$500 you want to be, and what you plan on using it for mainly (plinking, target, hunting, etc.)
The Ruger 10/22 has a large following, but a lot of that seems to be among those who are customizing them and improving the factory accuracy. Nothing wrong with that, but it can get expensive. My favorite .22 semi-auto plinker is the Marlin M60. They're certainly within your budget.
If you like lever guns, few things are better than a Marlin 39A, although that's near the top of you wallet.
For a great bolt action, you need look no further than a CZ 452. The Trainer model is modestly priced, and the fancier ones are right under $500.
The same decision needs to be made regarding handguns. Revolvers can run from around $300 for a Ruger Single Six to $700 for a S&W model 63. Same thing goes for autoloaders. The Browning Buckmark and Ruger Mark III are affordable and good buys. I like my Beretta M87 Cheetah, but at $650 it's above your limit.
Good luck with you hunt for a new toy!