I have never been to a BJ’s and think they are more on the east coast. Costco and Sams are it around here. Yes, you definitely get large quantities of certain things. It may be a great price per unit but I know that a gallon of powdered garlic is going to spoil before I use it so I am best to buy normal sizes at other stores. I only buy toilet paper like once a year. Laundry detergent is also a similar deal. Everything just comes in such a large size. I know that is part of the deal but still.
As for car topics, they do sell batteries and tires at these places. My parents have used Costco for batteries and tires and seem happy with the service and price. I have also seen large quantities of motor oil. The problem was that it wasn’t a weight that I commonly need so don’t want to buy and store that much.
I was reading one of those clickbait type articles where you have to click though and avoid all the ads to actually see what you want about warehouse clubs. There are some tactics that they use to trick you like re-arranging things slightly every month or so. This makes you have to look around and possibly walk past something that you have to have once you see it the first time so you spend more money. They also put the shiny flashy things upfront. You always see that 72 inch bigscreen right when you walk in the door at any of them! Then there is the fact that the building is really stark and plain. The walls are all white and the floors are concrete. Then they put things out on pallets and the large cartons that they were shipped in. This makes the place look like you aren’t paying for the extras so think you are getting a good deal when it might not really be so great. Yes, warehouse clubs are nice but you have to be careful that you don’t buy things you don’t need or spend too much on other things.