There are some small white topped tupperware-like containers with clear bowls that are found at the dollar store. They are the cheapest soap sample containers I have ever found at just 10 for 1 dollar.
There are some smaller see through screw-top containers in various colors that are found 2/$1 at most all Walmarts in the travel section, which is usually right by the soaps and shampoos. That section is phenomenal for sample containers for wet shavers.
If you want to go more upscale, you can go to Ikea and get these containers called grundtals. They are cheap as well... 3 containers for around $7, but they look incredible. They also hold a whole puck, have a see-through top, and have a magnet on the back that gives some awesome storage options.
Daiso Japanese dollar store sells a tin that is white metal on the bottom with a translucent lid. That container can be found at Daiso Japanese dollar stores for $1-1.50. They are offered in silver metal or white metal. They are best for very large soaps or if you really like to lather within the tub.
Breakdown:
I recommend the Walmart screw-top colorful containers for samples or if you are traveling, the small dollar store containers if you are low on funds or just need a LOT of containers, the Daiso Japanese containers for large soaps or lathering within the tin, and the Ikea grundtal if you want the all-around best container that is also the best looking.
You can also get more upscale containers on eBay, Etsy, and Amazon, though at higher prices. Apollo is one of the most popular. There are many options for metal, wood, ceramic, plastic, etc. containers.
I hope I haven't lost you with this long post, but I have tons of experience with this since I have hundreds of soaps. This info cost me a lot of money to find out, lol.
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