Welcome to the LOC!
Here are the rules about buy/sell. I don't think that you can make a donation but you could become a GOLD member...but I still don't think that you would be able to post in BUY/SELL but SW could answer that for sure. Either way just keep posting...it won't take long for your status to change...and then you can post.
Rules
If your status is New Club Member then you are not allowed to post items for sale in this forum. You must make a contribution to the forums before you can post here. When you have made enough posts, your status will change, and you will be allowed to post. This has become necessary due to the number of people registering purely to sell, and not contributing to our community