It is better to avoid the idea of renting a signature until you have a sufficient history of posts to judge the quality of what you post, lock the topic and come back again after 500 to 1000 replies then your chances will be higher if your are makin high quality posts.
Yeah. I also had a look at your post history, @OP, and I noticed that most of your posts are on local and Off-topic boards. A company or even an individual willing to advertise something wouldn't pay you for posting in these two places only. Your posts need to be spread around the forum for more visibility because that is what a promoter wants, more visibility.
So, as suggested by @hugeblack, you should rent your signature once you think your posting habits are good enough for someone to advertise a platform or service through your signature. And most importantly, improve your post quality so that you can get merits and rank up so that you can at least have some designing in your signature.