Part of thrift store shopping is not knowing what you will find. I recently stopped at one looking for something else but instead found this set of magic bullet cups, juicer and blender for $5. In the past few years I have purchased two other sets that included the base for about $5.
I purchase items such as this when I find them on sale as a backup in case my other one quits working or the cups break. Another item that I buy extras when I find them for only a few dollars is the Salad Shooter.
When shopping at a thrift store, you are not as likely to find specific things you are looking for. But if you have a list of items you are looking for you may be able to find them over time.