Forum Moderators: martinibuster
Value of PR Lift
Guess how much this will help your own PR, guess how much you will rise in the SERP's as a result, calculate how much incremental $ you will make. If you don't know these things, then guessing and seeing how it turns out is a fabulous exercise.
Value of Organic Traffic
Guess how much traffic you will get from the links themselves.
Add Up the Values and Decide
The sum of these two sets of values should help you decide whether or not to buy the link. If you break even or better, chances are it's worth it, because you'll find ways to tweak in future that will improve performance.
Do not discount the value to your business if guesstimating and post-evluating. It will make your future guesses increasingly more accurate, and your investments more savvy. ;-)