They are great, I have owned a couple of AE82's (3 ATM, 1 4AC, 2x 4AGE's), you can pick the 4AC AE82 up from ebay from $500 (normally have 220,000 + km's on them) up to around the $2800 mark but you can pick up a twincam seca or hatch in average condition starting at $700 and pay anything up to the $4000 mark.
Here is a pic of my $700 Twincam bargain, It sat for a few months when the previous owners had it and it sat in my back yard for a year when i 1st got it, it had 317,000k's on it, Tiny bit of rust in the back guards(fixed), Needs valve stem seals as it will blow a tiny puff of blue when it 1st starts, Needed tyres (swapped them over from my other seca), It will get a buff eventually, I got it registered back in September and havnt had any hassels with it.