There will always be scams with any new value exchange system, especially one which guarantees the anonymity of the internet. But thankfully, BTC and ETH are still going strong, along with a handful of other altcoins. Since you've mentioned the decentralization of money, I think this can only happen in a completely transparent system, that's also geared toward mass market usage. Two projects on the Ethereum blockchain that could work out this way are AppCOins and Nucleus Vision. Their not based in the states, I suggest you check them out, although I'm not sure if it will be possible for you to participate in their token sales from Iran. You could find out on their Tgram group tho - https://t.me/nucleusvision