Hi,
There is alot of ponzi scheme's websites for bitcoin, some actually paying, but for Ripple (XRP), there is only one:
https://xrpdoubler.comThe min investment is 200 XRP and max 5000 XRP.
I'm very happy for this service as it is getting alot of activity and many deposits because its the 1º Ponzi for this coin, and that will make the website work and pay 200% Investments in few hours.
I'm just sharing this site while its still paying.
Of course there is allways a risk, but as it is the first service working for this coin, it will work for some time.
Why have these sort of scams instead of honest job trying to make money?
SCAM written all over it, avoid this website !