what got me into the amd game was the k6 series at the time I was looking at a PII
which meant new case, power supply motherboard etc, or I could get a K6-2 run it on a 66mhz bus and drop it in the machine I had later on getting a 100mhz fsb board
so yea I got a 400mhz chip and ran it a 366 for like 90 bucks, and I would do that to old laptops as well, heck up until last year I had a old socket 5, pentium 150mhz mmx laptop with that same setup in it (for a socket 5 you have to remove a pin)
and up until recently there was a very large bang for buck gap, though its narrower today (but considering all three of those machines were sub 300$ gamers as totally new machines and beefy video cards etc its still a good choice for me)