Hi Walter, thanks for the A2A, Reading your reply to Tam McTavishes request for clarification makes for a simple answer:
A cheap walmart school backpack would do the job, all it needs to hold is a set of toiletries, a change of clothes and a towel and maybe a set of shoes or sneakers.
You're right about the composition, yes, that's probably all you need, but about Walmart, are you serious? Are you going to buy yourself a basketball backpack , on this site when there are a lot of fake reviews, my friend, why are you looking for such complicated options, try following the link that I left, there you will find a bunch of options that you will like and you will choose everything you need from backpack to motorcycle))