At levels above "webmaster welfare" (as my SEO friends call it), you can do direct ad sales or affiliate ads.
A smart guy once suggested to me that when trying to sell ads on a semi-successful site he would "give" one of the six ad slots to an affiliate-using merchant by using their standard affiliate creative in the slot, and watch what revenue was from that. That would both give social proof to the site ("Look! It already sold one ad!"), and give him a floor to establish prices on the remaining inventory. If you can make e.g. $60 a month with on affiliate ad, then charge everybody else $100 a month for the same slot.
Apparently, in many niches, "Your ad in this space. Click here." works well enough to sell out inventory for small sites. There are many, many options for you if you want to make it a self-service thing rather than a "Email me, hammer out an agreement, and after you Paypal me the money I'll add your link directly in myself."
[Edit: At higher levels of deviousness it occurs to me that why have one filled slot and five empty ones when you can have five filled slots and one empty ones. This space is going, going, gone -- get it before it becomes booked!
Don't like affiliate ads? Advertise your favorite OSS project. You can always rejigger things once your "last" spot sells, dropping one of the donated "ads" from the rotation and freeing up another "last" spot.]
What you're calling devious is what most of us would call effective use of marketing psychology. Cialdini has written a bunch about it, and I think it's gotten into the collective marketing consciousness as the "scarcity principal". It's used everywhere else ("Act now! Supplies are limited!"), why not on the web?
I'm going to assume the OP is calling all marketing psychology devious. Would you not agree? I know devious has a harsh connotation to it, but strictly looking at its definition, it seems to fit with your last two sentences.
A smart guy once suggested to me that when trying to sell ads on a semi-successful site he would "give" one of the six ad slots to an affiliate-using merchant by using their standard affiliate creative in the slot, and watch what revenue was from that. That would both give social proof to the site ("Look! It already sold one ad!"), and give him a floor to establish prices on the remaining inventory. If you can make e.g. $60 a month with on affiliate ad, then charge everybody else $100 a month for the same slot.
Apparently, in many niches, "Your ad in this space. Click here." works well enough to sell out inventory for small sites. There are many, many options for you if you want to make it a self-service thing rather than a "Email me, hammer out an agreement, and after you Paypal me the money I'll add your link directly in myself."
[Edit: At higher levels of deviousness it occurs to me that why have one filled slot and five empty ones when you can have five filled slots and one empty ones. This space is going, going, gone -- get it before it becomes booked!
Don't like affiliate ads? Advertise your favorite OSS project. You can always rejigger things once your "last" spot sells, dropping one of the donated "ads" from the rotation and freeing up another "last" spot.]