Advice on a craigslist deal

I have an 89 with an auto transmission (sucks) and this guy is selling a rb20 with no ecu,harness, or turbo for 500.it does come with the transmission. I'm wondering if it would be more cost effective to go this route than getting the full clip for an sr20? I'm planning on doing the swap soon and don't know which route to take. Someone with experience got any advice lol?