How can I earn $ 15 + per month passively?

Hello everyone!
I was looking for a way to earn $ 15 + PayPal per month! I do not have a powerful computer or additional phone yet, so I've put aside cryptography extraction ideas and video sites like Smores.tv.
I would prefer passive gain methods, but I am open to other sites. I also use test sites, but I find them unreliable and most tests seem to happen while I sleep and miss them.