Make you can make a link page for advertisments
Im sure a few people wouldnt mind paying you a bit to have their link on a high traffic forum such as this...
<img src='http://www.ownster.com/forums/uploads/post-10-1076044411.jpg' border='0' alt='user posted image' />
<a href='http://www.cardomain.com/id/dubumbz' target='_blank'>my car @ cardomain....</a>
<a href='http://www.ownster.com/' target='_blank'><img src='http://www.bmw-forums.com/forum/uploads/post-4-1075256000.gif' border='0' alt='user posted image' /></a>