What Jehro55 said. Purchase the 5 gallon paint strainer bags from the hardware store to use for the grain bags (they're cheap). Most average strength ales can be made with a 3# bag of dme or 3.3# tin of lme plus 3-6# of grain in a brew in the bag partial mash. Learn yeast washing and you can use every pack of yeast for 3-4 batches. Brew low hop beers. When low-hopping isn't possible bitterness additions can be Magnum or similar high alpha hops saving perhaps a couple dollars on hop cost.
Many will advise against it harkening back to ye olde kit-n-kilo days, but... Most beers can do with using table sugar for 10% of the fermentables. If you do this though for average american ales for example you'd be wise to raise the mash temp by 2 degrees to compensate for the thinning the sugar is going to give you.
Finally beer calculus is a wonderful free online beer recipator to help with putting together your own recipes.