I just put one together after reading many different how to's.
Don't skimp on the size of either pump. PERIOD
You will regret it if you do. For a two bucket with a separate rez, you need at least a 300gph water pump $40 HD along with a manifold $5 HD, unless you went with two 100gph pumps $20 HD
For the air pumps you will need at least two that will handle a 60 gallon tank if you get aquarium types $20-$30 each or this is a great air pump to consider Coralife Super Luft Air Pump about $60 online
Air Stones- you get what you pay for. BUT when you pay higher prices for ceramic stones, you are paying for stones that don't clog up readily. The cheap ones work fine, they just don't last as long.
However, really just a weight tied to the end of the tube holding it under water would work fine, it is just a bit loud.