https://minergate.com/a/1b7b265e50e0336c6d241fda is a really good way to earn some extra money. The best mining setup is Monero(XMR) with XDN merged mining. It will give you the best results. XMR is ASIC resistant. You can do some decent mining even on an old laptop.
Just don't expect massive earnings. But then again, few coins can end up being worth a lot in few years.