Nope. Cost is dependent on rarity AND whether the item level is above your level. I calculated this awhile ago: The idea is that you can't "jump ahead" in item level so easily. Thus, a new player can't just buy "THE BEST ITEMS EVER" by sinking cash into pizza into gold into items.
You're meant to be farming the rare items instead of buying them. The store mostly exist to allow you to get that 1-2 items you're lacking in but need for your build, instead of allowing you to buy everything you need. Initially, just buy the good common/uncommon, especially from the lv 6-16 shop. Those are not just cheap, but are actually quite good/useful both for pve and pvp.
