Yes if you love to shop (most students do) you can get paid to become a mystery shopper. Retailers always want to see how good their customer service is, and therefore use mystery shoppers to feed back on the customer experience in the shop.
You are usually paid in cash or vouchers, and are sometimes allowed to keep the goods you’ve bought with the cash you’ve been given to spend, which is great if you would normally buy stuff from the retailer - if not you can just sell them on ebay for some more cash. Check out the following sites for more info:
