They are. We have both mostly for convenience; some cities only have one or the other, or they're on opposite sides of the city. I've found vacations and week long trips are a lot cheaper if we hit one of the wholesale clubs and spend $200 on the first day for various stuff for the week versus spending $30-100 per meal eating out every day or getting ripped off at the local grocery store for subpar stuff. Lots of Costcos and Sams have diesel pumps as well for when I'm working, and again they're 20-40 cents cheaper. A 20 cent difference in price per gallon for my work truck is $35 back to my pocket per fill up.