shed plans

Hello all, I am planning on building a shed soon. I'm thinking 8'X10' with a slanted roof. With a slanted roof, I wouldn't have to make rafters or trusses or anything. I've seen smaller sheds with that type roof, but will it work for a bigger shed? Also, a friend of mine said it was cheaper to just buy the kit from one of the big box stores. Is that true? Anyone have plans for a simple shed (8'X10' or thereabouts)? Thanks, Roger.