Yobit accept PerfectMoney
YoBit are absolute scum and no one should care what they accept.
On the subject of Bittrex, you're right that you can't deposit fiat. The majority of people trading these altcoins are hoping to end up with more BTC, and alts are typically traded against BTC.
You can buy with fiat if you find someone to execute the trade, but there are no
trustworthy services at which you can deposit fiat and buy small altcoins.