First there is costly, costly it's used when you express that something costs you much money and you didn't expect to hear all this cost., but it's not said to the stuffs are being selling in shop stores. 2and then there is pricey, pricey means expensive we use it with informal situations. To talk about about places that are expensive and have like such expensive shops. Expensive grocery stores, we describe as they are exclusive for formality or we could say fancy. For some examples. We had an apartment in very exclusive part of the town. We stayed in a fancy hotel in Brazil
