I haven't actually done it as I'm just getting into the world of crypto, but I think at the present time you can't. You have to buy bitcoin or other cryptocurrencies that are tradable with STEEM. Coindesk.com is where you can buy bitcoin with USD and Bitrex.com has the option of buying STEEM with Bitcoin.
@silverstring is right, you have to buy it with bitcoin. I bought bitcoin at coinbase and then sent that bitcoin to my wallet on bittrex.com, which is where you can buy steem with bitcoin.
I haven't actually done it as I'm just getting into the world of crypto, but I think at the present time you can't. You have to buy bitcoin or other cryptocurrencies that are tradable with STEEM. Coindesk.com is where you can buy bitcoin with USD and Bitrex.com has the option of buying STEEM with Bitcoin.
@silverstring is right, you have to buy it with bitcoin. I bought bitcoin at coinbase and then sent that bitcoin to my wallet on bittrex.com, which is where you can buy steem with bitcoin.
Sorry I think I meant to write coinbase not coindesk.