9mm would probably be a good choice for you. 9mm ammo is cheap enough to plink with regularly and is still an effective self-defense round. If you are considering a Ruger P95, I'd approve. I've had 7 of them and have never had a problematic one. You can find them used for $250 bucks, and brand new for around $300. The triggers are pretty mushy, but it is a soft pull that you will get use to after shooting it a while. They are a little on the big side, but still easily concealable with the right holster/positioning. The best thing is that you can find aftermarket mags, high capacity and factory capacity magazines for under $15.00 to use at the range. Kahr is a great gun too, but if you are on a very tight budget, the P95 is fine.