They come in two different lengths, 35mm long (standard) and 45 mm long (XL) Carto's. I have 2 tanks that I use for the standard, a glass tank from High Desert Vapes (if you go that way make sure that you pay attention to the length of the tank, they vary). I also have a Prive tank. Both of these are on the expensive side, the HDV was about 50, the Prive was about 65. I have read good things about IBTanked, and they come in both lengths, I believe you can get a kit for 25.00. The other one that has rave
reviews is the Phiniac, again comes in different lengths, and is around 50. I'm sure there are others, I don't remember seeing a more affordable tank (like a smoketech DCT) in the standard size.