Probably the best way to invest is to find a site that gives you the best price in return. Check out new marketplaces based on blockchain. Its one of the most secure ways
I think this is a nice way to get yourself scammed, there are many sites that makes promises about high returns and then people realize too late that is nothing but a scam, it is better to get smaller earnings since the risk of getting scammed goes down significantly, remember if it is too good to be true then most likely is.