There was a long post about the best chems just earlier in the week.
Basically all chems are the same (my position on this subject) and if your dealer sells chems at what you consider a reasonable price by all means use what they have and support your dealer.
But if you're going to pay too much for anything there are alternatives. If you do look at alternatives, make sure your getting the "equivilent" stuff for the money.
BTW, a cheap alternative to alk up IS baking soada - same stuff and way cheaper at the grocery store ($0.79 for 2 lbs).