This scam is similar to the My Shop Scam.
A user with a My Shop says something like "Giveaway my den when my items are bought" or "Selling rare spikes for gems when my shop is sold out". This may be a lie to quickly get diamonds for their decently-priced items, which is harmless (but still dishonest). However, if the items are overpriced or unwanted, it's a scam. Either way, they won't follow through with their promise.
How To Avoid This Scam
The only way to avoid this scam is to not buy from the user's shop. This is usually, if not always, a scam. You can ask the user some questions to make sure it's a scam, or to persuade other users that it's a scam.
- Ask the user what they're giving away, and see if they have a response.
- Tell them to wear the item they promised or put it on their trade list. If they won't do either of these, it's a scam.
- If you're still not convinced it's a scam, buy the cheapest items (if there are any) and see if they keep their promise. If they ask you to buy more items, it's a scam.