Some vendors sell Poe currency on the Internet, such as VHPG. Their website is big, but only Poe is a game. You can search for POE currency directly. This is also the domain name.
I also accidentally clicked on the website, which not only sells Poe currency, Poe orb, Poe items, noble orb, etc., but also occasionally provides free game guide, communicates with customers and obtains coupons before purchase. Last time I bought, I still offered a 5% discount and made a good profit.
The whole transaction is no more than 10 minutes, very satisfied.