I just came back from Estonia (which was incredibly cold by the way) and while I was there I picked up some Transformers knock offs. Knock offs are toys made using the same designs, or even the same moulds in some cases. The big difference between them and the real deal official toys tends to be in the quality. The plastics are very cheap and brittle, so although they look the same they’ll fall apart if you try to play with them. They also tend to be different colours to the originals and are unbranded, meaning the toy I bought wasn’t called a Transformer; it was called a ‘Vehicle Transformable’.
For collectors these toys aren’t worth much due to their cheaply produced nature, but they do represent a chance to get toys that would otherwise cost you a great deal of money, if you could find them at all. One of the the toys I bought was a G1 Onslaught, which is very hard to get hold of these days.