Actually, you can REFILL those small, travel/sample size tubes of toothpaste (just put the nozzles together and squeeze)...
I know. I've gone high-tech with this by gluing two caps, back-to-back, then drilling a hole through them. I take an empty small tube, squeeze out the air out, then using my device, connect it to a full tube of toothpaste. Squeeze the full tube to transfer paste to the empty tube. It works well and there's no mess as there can be if the two nozzles aren't perfectly aligned.
I notice that I'm not the only one to come up with this idea. See Toothpaste Refill Cap