For the pricing of Megs, you could just look at their site and that's pretty much the MSRP/going rate. You might get some stuff like
NXT and Gold Class a bit cheaper at Wal-Mart but the web price will be a good reference point.
Regardless, it's cheaper to buy them in the States, although Chris at eshine has some pretty good deals at times.
Did you mean Chemical Guys? I've never heard of a wax company called Chem. Bros. If you did mean CG, you probably won't find it at any retail stores.