I'd say retail through someone else's site.
They'll be able to talk you through what you need done, if it's all legally airtight, etc...
Getting this information from people who have done it and know what they're doing really helps greatly.
Everyone wins in a situation like that, as you get a percentage of a sale, the guys who sell it do, your not held liable if anything goes wrong ... plus extra traffic for that company.
It also solves the whole problem with 'self-employment retail', as registered companies get certain rights conserning retail which individuals do not.