I buy stuff on Amazon all the time and occasionally eBay, (what alternatives are there?). In fact Amazon is my preferred retailer. If I am not happy, Amazon are excellent about refunds. 99% of items are ok and at a good price.
I recently bought from Amazon, two wall plug outlets with USB charging sockets included. In one of them, the USB sockets didn't work. I reported it to Amazon. A return was arranged. I took the item to a drop-off spot in a small local store. I didn't even need to wrap the item up, the shopkeeper put it in a returns bag for me. When I arrived home, my account had already been refunded the cost of the socket.
I don't really care about the likes of Amazon and Google gathering 'Big data'.