The Dollar Store name is a misnomer as not everything is always just a dollar, but their prices are cheap and I go there a lot (or send the wife there). A few reasons:
Walmart sells razor blades for my style of razor at about $12 bucks. I can buy the same amount for $5 at a dollar store.
I use a lot of bleach on the farm...elsewhere it is $3 a gallon. I can buy it there for $1
I have 4 daughters and one always has a birthday party to go to. I can spend $14 bucks on a toy gift at Walmart or go buy some cheap thing there for $1 or $2.
Really the list is endless. You would be surprised at what Dollar Stores have since everything is not just a dollar inside. Food, medicine, cleaners, supplies. It just makes sense in this day and age to save a few bucks when you can. Since the stores are close by, or on the way to Walmart...it is just an extra stop and not out of the way.