You can get some nice ones, but axanthic, leopard, pied, and banana aren't going to come cheap. You could probably get a het pied or axanthic for cheaper, but still not very cheap. Leopards have also proved challenging to find at the shows near me, but you might have better luck.

4 or 5 snakes for 600 gives you am average of 120-150 per snake, which isn't going to get you much besides some single gene snakes and maybe a het or two. Don't be afraid to ease back a bit, maybe just go for 2 or 3 good girls and start saving a little more money for the next show. You're mostly going to find babies and maybe a small handful of proven females (personal experience says they're going to be normals, pastels, spiders, and pins with the ocasional albino thrown in, but like I said before, maybe you'll have better luck), so you can feel free to make use of the proven females while making a bigger investment in some good hatchlings. Not much of a rush on the little ones, so take your time and feel free to be picky about what you want.

You seem like a deal hunter, so I'm sure you'll be able to build a good collection for a good price. I'm very satisfied with my starting collection of 8 snakes, and my records show me that I paid 973 for all 8 of them including shipping and tax. Looking back, I would have been a little chooser with my females, but I'm still happy with what I have.