I'm a new user, so I apologise if this has come up before or even exists already,
It strikes me that a good further income stream would be to set up links into Amazon.com (and Amazon.co.uk etc they seem to be separate schemes) using their associate program. If I read it right, it's a minimum referral rate of 5% and it doesn't have to be links to particular items.
This gives an opportunity for Spamgourmet users to earn you some money to keep the service running without costing themselves anything, just by entering Amazon via Spamgourmet.com.
Set up a link to Amazon.co.uk and you'd probably get commission on $30-$40 of purchases that I make anyway each month.
Tim