Also note that it may be some time after Kickstarter fulfillment before you start to see expansions hit the retail market.
Typically what CMON does is release the base game to retail early and then trickle out the expansion stuff months later month to month. if you look at the Zombicide black plague release of expansions you get the idea. They are still releasing stuff for that game which is almost over a year old now. Bottom line if your ok with waiting eventually you can buy all the expansions at retail.