How to do a lottery for a free diaper?

[tracys]

I would like to do a lottery to give away an EUC Goodmama. For mama's to enter, I would like them to donate food to a local food bank. I'm thinking I should ask participants to post a picture showing them donating. I would like to have the lottery open at least a week to hopefully get a good number of entrants and then the winner will be randomly selected. Can I do this here on DS? If so, where should I post it? Thanks in advance for any help!