Works only exclusively on Steam, Doesn't work for Epic or GOG. also gives prices for Steam, Steambuy and SteamPay only.
which is outer merchant of Steam!
I need the price on the official websites including (epic, gog, itch.. other official stores).
Again works only and the plugin show up only if you are in steam website the (official). which I can search/wishlist in Steam manually.

The Steam popup is awesome! Bought PUBG with a discount :D
Thank you)