Originally Posted by Tempest

A recipricol link is usually some sort of text link or small banner that you put at the top of your gallery. Usually the TGP you're submitting to will supply you with the banner or text they want. So you put 3-5 of those at the top of the gallery and then submit that gallery to those TGPs. The TGPs want that as a way to exchange traffic between their sites and also to get PR.

Who is it that's dictating what sites you can and can't put up there?

You'll find a lot of "free" submit sites in the smaller area, i.e. 20k-50k type sites. You can build up your experience etc. by submitting to them and then work your way up to paying for the bigger traffic. Don't let yourself be brainwashed into thinking that it's only worth submitting to the big pay per submit sites.