Lol...I did something similar back in Wrath. I logged into a second account, and on my main account, I posted an item to sell in trade for 'best offer'. As soon as someone started to bid, I'd use my second account to inflate the price. If my second account ended up winning because nobody else would outbid after a certain point, I'd whisper the last bidder and tell them the winner logged off or something :-) I sold so many things that way.
Is it scamming? Sure. If nobody finds out, or hell, even if they do, who cares? It isn't anything blizzard is going to cry over. It isn't the sort of scamming they're interested in. You aren't stealing anything from them; they give you gold, you give them the item(s). While they may have paid an inflated price for it, it still isn't considered stealing.