I used to buy a lot of raw chems from them too. But shipping got too expensive, and I've just found it easier to buy chems that are premixed to do a specific job.
One bad thing about the Chemistry Store is that they only ship caustics via Fed Ex, which means you pay shipping, plus a $20 Federally mandated Hazmat fee.
If you can accept shipment from a commercial line, like Roadway for example, you don't have to pay the additional hazmat fee. Larger chem distributors and suppliers are able to take advantage of the commercial carriers and save you money.
I have to mention here clearly that it can be very dangerous to mix your own raw chemicals. You better know exactly what you are doing and be sure to wear appropriate safety gear.
One mistake, and you could create an explosion or fire, not to mention life threatening situations. It's not all about saving a couple bucks.