Not only that-look at what you're doing to yourself. Even if you do manage to sell them to someone who sees a long future for your site, what if you get crowded with links later, when you have a PR 5 and those spots are premium? Jumping the gun like that won't get you very far. You can get a dollar for ten minutes service, if you need the cash so bad.
Gotta go with amanamission, if you're serious about your site don't sell lifetime links, especially for cheap.
I am also with amanamission and Roman. It's just not a very good idea.. Plus, if it becomes a link farm, that'll be even worse.
don't sell lifetime links for cheap but if u need money ask them that you would keep till 2yrs or what ever and give price... $2/yr......