They are usually in with the cleaning supplies or in with the housewares at Dollar Tree. You can also buy them directly through the web site. https://www.dollartree.com/search/go...e%20eliminator
With any discount store you have to carefully read packages to weed out the knockoffs from the overstock and sample sizing of the real deal. I have also used these moisture packs along side of the pricier ones from the regular stores and find they work just as well, if not better than some of the same brands, and contain the same ingredients.
Great items dollar tree sometimes carries is Reynolds Wrappers (precut foil sheets) that we find invaluable for camping, and the small sized Brillo pads.