The problem with "estimating" is that prices are different in all areas. In Canada, expect to pay $2500-$3000 CDN for a 20V or GZE swap and more if you're going with a Haltech standalone. A decent motor alone will run you about $1500-$2000, sure you can find Silvertops for about $500-1000 but most of the time they're not complete.
Body work will depend on the condition of the car, if its a rust bucket (in Canada they tend to be) is not gonna be cheap nor easy to fix, remember its an 18-20yr old car.
As for performance parts.. this ain't a Civic, so your local rice shop most likely won't carry parts, and if they do; be prepared to shell out mad $$$$.
Don't go into this project thinking.. Wow! I'm gonna do up an AE86 just as fast and easy as I did my *insert your past project here*! because if you do, you're better of going with an S13/S14 than an AE86.