The least expensive sprint bars that I would suggest are the Nitto B123 and Nitto B125. The steel are less expensive than the aluminum alloy. These bars have the same general shape. The only significant difference is that the B123 have more reach and deeper drop than the B125. I have Nitto B125s on my bike right now.
These have a 25.4mm clamp area, so you'd need a 25.4 stem or use shims. Shims are fine. They are a pain to setup sometimes, but they hold strong.
World Champions have used those bars...recently:
There are many good bars out there like the Easton EC90 Track and 3T Scatto. But those get expensive. There are lots of less expensive options, too.