If anyone is buying parts through HobbyKing, when there is a part you want, before you add it to your cart, leave the item on screen until a message shows up in the lower left corner offering it for a discounted price. It isn’t much of a savings but every bit helps.
It really is a one-time thing, though. So for maximum savings, use a different browser or delete your cookies before you start buying things!
I tried to fill up a whole shopping cart of discounts once, after two or three items the discounts stopped.