Here is a frugal tip that I think is also great for the environment at the same time. When I shop at Menards, you have to self-bag your purchases. Instead of using the regular sized plastic bags, I grab the extra large bags under the counter to bag my stuff. Then, at home, I use those extra large bags as my garbage bag liners for my kitchen trash bin.
These large checkout bags fit perfectly in my kitchen trash bin. They are even stronger than many of the "trash bags" we have been buying for about 25 cents per bag. When full, I simply twist the hand straps together to tie off the bag.
You might want to see if other stores offer these larger bags at the checkouts. Instead of grabbing the smaller regular-sized plastic bags at the checkout, take the extra large bags and reuse then for your trash bins.
You can use the regular-sized plastic checkout bags as liners for the smaller bathroom trash bins. But we don't use many bags in the bathrooms. If you have a choice of bags at the checkout, grab the extra large bags next time!
To me, being frugal is both having the patience to wait for a potential lower price, while at the same time having the shopping knowledge to jump on a good deal when it comes around so you don't miss out.

Of course, this time of year, we don't need insulated bags for frozen goods when the outside temps are -16F! Maybe better used to keep things from freezing on the way home...