Calling this little box the “Tiny SIM Card Spy Ear” is confusing literalism the way only crapvendor Brando can do it. Here’s what it does: It’s basically a cellphone in a box with a microphone, letting you call in to its phone number and listen to whatever it can hear.
It works on GSM only and charges over USB, so I’m presuming that means it has a built-in battery, as well. At $65 it’s not exactly cheap for all that it actually does, but spy craft is not a poor man’s game. (Unless it is.)