I don't think there are any cheap slot A processors. Any around would be classic Athlons, not T-birds. Any slot-A T-bird you find with be a year old, at least, and selling at a premium compared to the socket models.
This motherboard is in my system I built in May, 2000. Its a first generation VIA chipset board. Its OK, but I think current offerings (like the ECS motherboard I just got for $65 are far, far superior-and you can put a cheap Duron or T-Bird in them.
I don't think I would buy the KA-7 again. AGP never worked except at 1x, major problems with SB Live!, etc.