I've seen this too with most of the dealers who list on eBay and Vcoins. I assumed it was because eBay had a higher seller's fee than Vcoins. On one occasion I actually bought the higher priced coin on the eBay listing also available for less on Vcoins, because eBay had sent me 15 or 20% voucher which made purchasing the coin slightly cheaper via eBay. I do wish the Vcoins company would occasionally provide a discount code for their platform, but at present it is just up to individual dealers to offer discounts I guess.