Yamaha isn’t producing the DTXPLORER kits anymore, so you either have to buy them from a music store that still has them in stock, or you need to buy one secondhand. The best places to find secondhand electronic drum sets are Facebook Marketplace, Craigslist, and eBay. However, I wouldn’t advise buying a DTXPLORER as there are modern kits available that are far better in quality. You may even be able to find a newer kit for the same price.