My players got a couple Glue Bombs off some Kobolds. You can throw one of these things to restrain creatures (they get a reasonably easy save) until they break free. The players made good use of these bombs against some fleeing enemies, so they want to have a couple more on hand for future encounters.
Considering the originals were made by Kobolds, I'm guessing they weren't altogether hard to make. Likewise, I would imagine they can't be altogether expensive to pick up a few.
What might a Glue Bomb cost? Alternatively, is there another, somewhat similar item I might base the price of a Glue Bomb on?
(I notice in the PHB that Alchemists's Fire is 50gp. That seems high to me, but I'm not really sure.)