I am currently offering bands logo and cover art for free to include in my portfolio. I only ask a bit of band merch would be desirable for my trouble.

I don't know how the hell i write up an agreement as i'm not charging money. A band have asked for an agreement so i don't claim that they stole my image etc.

I would like some general advice about this working for free thing and if there is a contract template out there i can use.