So you want a new idea on how to make profit? I wouldn't recommend the unusual market, but how else can you make keys fast?
I like high-value stranges and promos trading. Basically, you buy high-value stranges worth a lot for 1-4 keys under their value, depending on their value and on demand. Then you flip them for full value. It's criminally easy. Have an example:
That post made me dozens of keys. Just buy them for low, and immediately repost them for full value. It's an easy and great way to profit.