Firstly, I will point out that this isn't going to make you a load of money, but it's good for a bit of free cash every now and then. Qustodian is an app that you download to your phone. They then send you messages / adverts that you either watch or answer a question about, which they pay your for. It's completely free to download, but like I say don't expect bucket loads of cash. You can reasonably expect £10 every 4-5 months, though, and it's a good way to waste a bit of time while you're on the toilet!