Our Local store sells em and their collection changes about 3 to 4 times a year. I also have a craft store near by and they change collections there too. Must say tho, I have quite a few but I dont use them as often as I should. For some reason I keep buying them cause I like them but never seem to use them.
I reckon the collections may change due to request. If the shop you go to doesnt have much request for them or sells them a lot, wont change it much.
I order all of my embossing folders on-line because my local store has the same four to choose from that it had when I first bought my Cuttlebug. Try Hobby Lobby, Joann's, Stampin' Up, Overstock.com, Amazon, etc. You are bound to find exactly what you are looking for.