Not sure to which gimmick/trick that you are referring, but since Magma is the latest $60.00 dollar wonder being sold, and has a piece that could be lost, let's go with that.
Generally, and rarely, are there replacements for any utility such as this in this price range supplied by the vendor
Simply, you lose something, you buy another trick. Kinda sucks eh?
The exception is with smoke devices...especially the pricier ones. Replacement parts are sometimes available e.g. heating elements.
Now, if its a totally different trick, just post the name/link and you'll get a more specific answer.
Best wishes...