Non-negotiable: one sponsor and one text link per page.
Actual price of the main page: 0€ quarterly. (0€/month)
If the spot is taken, you may propose a price «raise» for next quarter. Two weeks before the end of the quarter, the incubent will be informed of the highest raise - if applicable - updating next quarter’s sponsoring price. The incumbent may «call» the price and keep the spot. The actual price will be updated and visible to all.
The sponsor will get one colored text link (adblock resistant - no JS) on the top of the main page and on the quarterly newsletter. 140 Unicode characters allowed. As a call for attention - quarterly - you may change the link color.