Not a scam, but very very sneaky. The 'dollars' they pay you in are paybox dollars, an imaginary currency, that they decide the value of. More or less it definitely will not be worth your time to join. They require you to earn a certain amount of money to keep an account open and you won't be getting enough money out of it to be worth the time invested.
In the future if you ever think something's a scam, do a google search such as 'paybox.me scam" if you get a lot of results you can be pretty sure it's not trustworthy.