Guys, need help.

Looking at a set of SSM stage 2 heads, lower intake, and camshaft. Whats a good price for these used?

 

Problem with used is that there are a lot of variables to take into account. In general I base value off of use. A new item in box that was never used should be discounted only 10-20% over original value (unless it's so rare its a hard sell then it could be more). A lightly used part (less than 50,000 miles) I'd look for about a 50% of original value. Anything above 50K I wouldn't pay more than 20% of the original value as odds are the part(s) will need light to moderate refurbishing that adds to the cost.