If you only want small amounts to be carried in squeeze tubes have you tried the following idea....?
Buy your toothepaste in the biggest amounts/size of tube available.
When you have used all the tothepaste cut off the closed end and wash the tube out carefully (you end up getting at least one more brushings worth out of the tube
) - there may be some residualy minty freshness flavour left in!
Fill the tube with your desired filling (some interesting flavours may result for the first few usages.....) fold over the end a couple of times and clamp shut with a STRONG Bulldog clip.
Bingo - squeeze tube for free!