NEVER buy any sort of storage of device on eBay. Seller ratings, or not, if the price is too good to be true? It usually is...
You just have to see that it is unbranded.
I bought a 32GB card for £10 for my GateWay card the other day. Branded card, in original package from eBay. No problems.
Got a 16GB unbranded a few years back, nothing but problems.