Sardi,
> Im hoping someone (possibly Ethan) can tell me the best (and obviously cheapest) material to use to cover these things. <
I agree with Glenn that Burlap is about the least expensive but effective covering you'll find. In England they call it Hessian, in case you're not familiar with the term burlap. The usual color is potato sack brown

but most fabric stores have a variety of other colors to choose from.
--Ethan