Yes Girl Scouts are an American thing. Girl Scouts is an organization for girls here in America to learn things about nature and that sort of thing. They sell cookies as a fundraiser every year. They sell several kinds of cookies. They are exspensive and yes you could probably find a cheaper alternative in a store.
No. Some can be exspensive if they are hard to find. I usually get mine from flea markets, yard sales, and antique stores so they aren’t usually that bad. They have cheap ones on EBay and in Thrift stores to.