>>6697555Not sure why the hyperbole, but it seems that you can pay up to 20 USD for these if you really want to.
Just search the term "infinity cube" on Aliexpress and you'll get a good selection to look through.
You should never pay more than 2 USD for a plastic one unless you get one with fancy printing on it, and no more than 6 USD for a metal one (and that's stretching it a bit).
I have two plastic ones and they're very nice for tumbling over in one or two hands. The joints are nice and loose and they make really satisfying clicking noises.
I have two metal ones. One has somewhat tighter joints so it takes two hands to play with it. The other metal one has looser joints so it's mostly okay with one hand.
You can also get these online from US sellers but don't expect to pay less than 6 USD even for a plastic one, so only buy from them if you need one right away (you don't).