A new forum now exists for that kind of offer:
Fundraising Swag !
If you are offering to provide something in return for a donation - for example, Ken's very generous offer of e-books of fanfic - post your offer as a new thread. State the minimum donation you want in order to provide your offer. Anyone can reply accepting the offer - again, in Ken's case, stating the specific fic you want as an ebook.
Make sense? If it's clear as mud, tell me
Wendy