You'd need a C&R and a sales rep from the company (whos name will be kept from here) in order to buy what they call a U Fix Em model for $70.
No telling in what you'll get though and if you had to buy a trigger group, you're in for way more than its worth. My suggestion is buy a shooter grade Yugo 59/66 from a number of online vendors and use it for blasting. You may even wind up with a really nice rifle just advertised as shooter's grade because it had stock damage or bluing wear.
The SKS is really not a project gun unless you're planning on buying a non C&R model like the Chinese, and then adding a scope, changing the stock, etc. I bought a U Fix Em because I had several parts laying around already and got lucky with a great shooter.
As for high capacity magazines... theres only 2 Chinese models that were made to accept AK mags and they are rare here in Mass. not to mention very expensive. The after market add on magazines for regular SKS' are illegal to use in Mass., and 99% of them don't work and will not feed reliably.
You may find something good at the Big E. One of the last gun shows I went to I found a Chinese military SKS that had a perfect bore and crown, but some surface rust and a refinshed semi beat stock. I was able to score it for $100 or less, I can't remember.
If you want something you can really tinker with, get a Romanian AK47. You can add all kinds of crap to them, most of which is illegal here in Mass. but the accessories and parts are cheap.