There's a link building service that offers $50 for 135 PR4+ DoFollow backlinks, guaranteeing to index more than 85% of the backlinks created (using links similar to Angela/Paul's).
Both services offer profile forum links. The backlinks are not contextual within relevant articles but are just standalone profile links.
So why would you choose to purchase the $50 service if you can get a big blast of 20K+ with a natural indexation rate over several weeks?
What is the value of the $50 backlinks in comparison to the others?