I didn't have any particular supplier in mind yet but on ebay, and Amazon ( for example this one, the difference in price from any of the vendors listed by Great Scott Gadgets (e.g. HackerWarehouse, or AdaFruit) is very significant. If you buy the Portapack + HackRF One from Hacker Warehouse the total will be close to $600. I presume these places sell them for the higher price but I'm not clear on what is wrong with the Amazon (or the eBay offerings) which allow returns.