I personally don't use them but if you plan on ordering, go to Amazon. I noticed that they are so much cheaper than the stores.

If I decide to order some Wonder Clips through ebay or Amazon - how do I know if I am getting the genuine ones or counterfeit clips?

I've never seen the generic brands try to pass as Clover brand. The generics will usually come in a tin or a plastic container, but clover would have their brand/logo displayed.

Bought my first set from wish.com, so much cheaper, and love them. They are original, but I can see where a bigger size would be useful with bulky things

I have some and like them. They are probably the original size. But I recently found that I can also use the clips used for paper from the office supply stores (or target, walmart) they are black with the wire clips. Sorry not good about describing them any better. They have been around forever, I'm sure you have seen them. They work well for binding and purse construction when pins won't do.

I love the original size. I use them for bindings and bag making.