2170 Cell Holders
Here are square 2170 cell holders in 1x2 and 1x3 configuration. Just 4 cents per cell hole. These fit 2170 cells perfect. All of these cell holders will snap into each other as well. For example the 1x2 and 1x3 will snap together.
If you want to build a 5x5 holder you can use 5x 1x3 and 5x 1x2 holders.