You should be able to do it for under $80. To make things easy on you, take some measurements of the bolt holes you have now, and look for seats that have the same/nearly the same measurements as 1st gen.
Easiest swaps will be seats from Toyota's first than other Asian imports, yet to swap European or U.S. buckets. Try to get seats with thin backs and bottoms, they wont reduce head and legroom as much, MR2 seats work really well. Most of the import car seats that I have swapped the outer two mounts and front inner mount have lined up, it is usually the inner rear that has to be drilled if it doesn't line up with the seat belt bolt hole. Most swaps I have done also require a spacer(usually a couple of washers) under the outer rear mounts to level the seat backs out.
