as for first question: ram is not traded on an external exchange, but internally on the EOS network itself (via the eosio.system smart contract), so right now the only way to do so is via the command line tools like cleos or eosc
as for second: this is version 0.1 so that feature hasn't been added yet (see "the plan" at the bottom of post for brief roadmap) but it will be within the next few weeks! Check back for updates, this would be the first tool I gui for trading eos ram online that I know of...
RE: Live EOS Ram Price Chart and Buying Calculator