I got a notification just yesterday about a sale from a shop because I favourited an item, and it instantly lowered my opinion. I don't even remember what the item was, and I didn't check their shop because of the intrusion. It might be a little silly of me to do that, but it makes a seller seem desperate - even if they -are- desperate they should at least try to maintain a cooler, calmer appearance! Facebook, Blog, Twitter, that's a great way to do it. Also, shop banner. Grab your banner then put a nice red "sale" mark on it somewhere - not so big as to look like you're clearing the whole place out (the bigger the sign, the more extensive the sale, I've found) enough that people might notice it. Plus, in shops, "Sale" is usually in red.