I have a friend who buys, fixes, and sells espresso machines yielding around $1000 profit per unit.

Go on craigslist and buy things that are significantly below market value and resell on ebay or otherwise. If you know your stuff about musical instruments there are plenty of deals to be had. I bought a mint condition Fender Deluxe Reverb off there for $500...Guitar Center price: $1200.....it's like I bought myself a great amp and $500 extra dollars!

I like to call the concept "buying money".