Very common is to breed brine shrimp. You can buy the eggs in any lfs. All you need is a soda bottle, airstone +pump and some small light along with 48hrs.
The only problem with brine shrimp is that they hardly have any nutritional value. The only time brineshrimp is good is when the yolk is still attached to the hatchlings. So if you decide to go this way make sure you feed shortly after hatching.