Depends on how you want to go about it. You can buy all the parts used from either a junk yard or some of the guys on here. Or you can buy a full parts car if you have the space, use the parts, and recoup some costs by selling the remaining scrap.
When I did mine I got quoted around 700-800 for all the parts used I think. Instead I bought a 5 speed E36 and sold the cats and extra stuff and scrapped the rest. Ended up breaking even if not making a couple hundred bucks.