If you keep your eyes open, you are going to discover that you can buy a lot of things you use in the process of building a model that you can find in other places than a hobby shop. And usually for a whole lot cheaper.
You don't say where you live, but if you live anywhere close to a larger metropolitan area, check in your yellow pages under Plastics. Most of them will sell you sheets of styrene in thickness of .010 thru .250 in pretty reasonable sizes and prices. For years I purchased styrene from Cadillac Plastics in Lenexa (a suburb of KC) and found that I was paying 1/4 to 1/3 of what I was paying for the same sheet at the LHS. Plus you can buy tools for scribing and cutting styrene that aren't usually seen in the LHS. And the plastic supply can supply you with bulk liquid glue. Usually the same brand as what you have been purchasing in the LHs and cheaper (lemme see $2.99 for a 1.5 oz bottle of cement at hs - $4.99 for a quart of the same glue at the plastic supply - that's a no brainer to me).
Hope this helps you a little.