I am beginning to get many requests for text links on some of my sites. I use TLA as well but there are many more requests for paid links than they offer. And of course, I would rather keep 100% of the revenue than 50%.
My problem, is how do you keep track of all the many links, their experations, pricing, what pages they are located on, etc. Seems like it would be a nightmare as you sell more and more links.
Also, sometimes I use hidden tags after the text link to remind me of info regarding that link. Does this hurt the value of the link?
A private page (http authentication should be fine) might contain a one or more PayPal subscription buttons. Being provided with a username and password, your customer could fill in a short form with his link details and then make the purchase.
Recurring billing would then be handled by PayPal and you would retain the details of the link in the PayPal subscription details.