What you wan't, if you are going to sell the space, is for the user to chose Ads from the plan, then have different prices on different locations. If the names can' not be solved, then I propose that you have 3 plans with ads: Ads 798X60 Bottom $12, Ads 140X600 Right Side $15 and Ads 900X80 Top $20.
Just a tought :confused: