There is no cost to join a project. In fact, there is a group rate that you qualify for when you order a Y-DNA test through a project.
To order a test through a group project, you can browse or search our Project page. If you have already tested and want to join a project you can do so from myFTDNA account. Click on the Join Project link and browse or search available groups. Once you select a group make sure you click the Join button below it to confirm.