Unlike most of the Surface devices, the new Surface Pro X and Surface Go only come with an USB-C port, so your existing USB-A based accessories cannot be connected directly. To solve this problem, Microsoft last year released Surface USB-C-to-USB Adapter which adds standard USB functionality to your USB-C port to connect flash drives, keyboards, and other accessories. This adapter regularly costs $20, but it is now on sale. For $10, you can get two of these from BestBuy.
Find the deal here on BestBuy. When you open the listing, it will show $24.99. Click on “Hot offer Save $40 Total on 2 Accessories” link below the price to take advantage of this offer.