I suggest that in order to buy other cryptos, buy bitcoin first on sites that accepts master visa card as payment for buying btc. One of the best site I know to do this is coinbase. IMO they are one of the most user friendly site out there that helps users buy bitcoin using visa card payment. You can also try changelly if you want to buy ethereum directly and then just convert it into other cryptos. Use the method that you think is more convenient for you.