I've noticed that since we began the process of selling our house and nearly everything we owned then hitting the road, my shopping habits have changed drastically. I used to make a list of stuff I needed then go to whatever store I happened to pass by and pick up everything on the list. I would look for sale items and maybe pull a manufacturer's coupon off the shelf but that was about as far as I went to save money on the things I bought. I also tended to buy lots more things in addition to the stuff I had on my list.
Now, not only do we buy a lot less stuff (living on the road and not having room to store stuff will do that for you) but the way I shop for the things we need has changed as well. Now I make a list of things I need (soap, shampoo, makeup, etc) and then I start my shopping at the dollar store. The dollar store is usually (not always) the cheapest place to buy stuff so everything that I can buy on my list at this store will save money over buying it at other stores. For the things that I absolutely can't find at the dollar store, I then move on to Walmart (fortunately all of the stores I shop at are in the same general area). If I can't find the things I need here, I will then usually head to Ross or TJ Maxx. I will also shop at thrift stores depending on what items I am looking for. A department store is the last place I will go to shop now.
The reason I shop like this now is so that I can stretch my money as far as it will possibly go. For example, I needed a mouse for my computer the other day. I had checked the price of the mouse at Staples a couple of weeks ago but the price was around $25! So, as is now my habit, I started at the dollar store. They didn't have any mouses (mice?) at all so then I headed to Walmart. Their prices were comparable to Staples which I thought was too high. Next I went to Ross but they only had a cheap mouse that wasn't wireless so I walked next door to TJ Maxx and found the perfect wireless mouse for $7.99 in their small electronic section. Score!
We do basically the same thing for groceries. We only buy loss leaders at regular grocery stores, we will occasionally buy food (usually snack type stuff) at the dollar store, and then we do the bulk of our shopping at a huge Asian store that we found which has excellent prices on most of the fruit, vegetables, and meat that we buy.
Along with only buying what we can use in a short period of time instead of stockpiling stuff and only buying the items on the list and no extra stuff, this method of shopping has saved us a great deal of money over just buying everything at one store.