Salvage yard 101... some salvage yards do 50% off on either a holiday or day after.
As for seats, My 96 has 260k on the odometer. My seats are horribly uncomfortable and I have spent the last year going over the best option for me. I just ordered two new corbeau sport seats.
1. Junkyard seats, I found several decent seats that were approx the same size. Most junkyards were from 75-150 for each seat, mostly depending on the brand of car. Then the color match would be off, so seat covers @150-200 for some good quality seat covers. Then mounting, I don't have the tools to make my own brackets, so you are at the mercy of a welder/shop to make your mounting brackets... @50-100?? So minimum 500. and you get used seats with a seat cover...
2. Toyota replacement foam, somewhere in the ball park of @250 for the pads. Not a bad option, but then you still have 17 year old seat covers. Then the passenger needs to be done as well so back at @500, prolly less if you shop for the foam.
3. DIY. Buy a block of foam @50 for a 4"x24"60" more than enough to do two seats. "have you ever done this? I haven't so no clue as where to begin" then seat covers back to the @150-200 for good seat covers. So @250-300 ish, and however long it takes you.
4. Buy seats. I paid 840, for the corbeau seats, that is tax and freight, which I feel the company should pay freight!!! And also the mounting brackets so they bolt right in. This is the most expensive, but I justified it because this is my DD, not a once a month rig, right now I drive almost 100 miles a day and CA traffic makes for some long days. I chose the most comfortable route.
my .02