You can usually get seats at a junkyard or on craigslist
You might also find some deals on replacement leather that someone somewhere bought at sticker price and never got to installing, or had the wifey tell em they didn't like the color
On my 3rd gen (police model), I got a full Eddie Bauer interior (seats plastics and headliner) off a junkyard for $1200 I think....that was a mistake, was in too much of a hurry and pulled the trigger on first set I found.
Later scored a full all-seat, all-leather kit off Craigslist for $250 (advertised @ $300)... some dude's wife vetoed it after he bought it and it just sat in his garage for years:
...and that's for 3rd gen, they still have new ones in the dealer lots. Most of em with worse stock "leather" thats really almost all vinyl except parts of the front seats.
Older models must have crazy good deals to be had if you search around