There a lot of extra income opportunities out there, it's for you to take which one is fitting for your schedule. If you're a busy man i suggest investing your money, it'll give you a passive income without spending too much time about it. If you have enough time, then i would say try buying and selling, you can check into products and take advantage of its price differences. With this, you'll be earning a pretty good amount of money and it's not that time consuming, you can still have plenty of time for yourself or work.