If you have to pay for a source, than you are getting scammed somewhere along the line. Sources, whether private or public, want to make money, so they aren't going to charge you just to see what they have. It's like having to pay to see the menu at McDonalds before you order. And be wary of anyone offering you a website where they openly sell gear. I know of forums where you have to pay to join, but not sources where you have to pay to see an inventory list.