What you gain with the Glock is something to seriously counter any hooligans who would try to change your way of doing things. People counsel that you get the 9mm hardware, so you can shoot cheaper ammo. I settled on 9mm as my standard pistol round, but I don't own one single cartridge that isn't a serious self defense load.
I think you'd be pleased to keep the Buckmark. You'll find that experience with it helps keep your pistol skills up, so you don't need to shoot the Glock very much. I enjoy hunting small animals like kangaroo rats with my Ruger auto pistol. The fun of the chase and actually hunting with the pistol is more important to me than whether or not I kill 'em. Sometimes, I use one of my Glocks for this too, but it just costs more and throws a lot more dirt.
Check out Cheaper than Dirt for relatively cheap .40 ammo. They have a 500 round bulk box from BVAC, loaded with the Fed. HST bullet, for $154. That shows up in the flyer they send, but this is an unspecified JHP for even less:
$13.10 per box is about as cheap as it gets, even for 9mm, so this should help.