Are these paid ranking packages worth it?

I need a keyword to rank at least first page. It is currently on page 3, but I don't have time to actually build the backlinks myself. I was going to try one of the packages found on this site but I need some opinions first.

How much would this cost me? Do they actually work? I don't want to pay $100 just to end up on page 2.

Also recommend me some services.