The cost depends on what you are after. We have quite a few options. For RV-7 and 9 (what we currently sell the most of) we actually offer the least expensive seats on the market (our CA-1 seats). We also offer the highest priced seats on the market (Aviator seats).
Sometimes customers see one of our seat options, and assume that is all we offer, but we've tried to give people more than one option.
Also, for more information about how we arrive at those prices, you can look here:
Classic Aero Pricing Policies
Just let me know if you have any other questions.