The market for popular alts will require you to purchase them with BTC... or ETH, or USDT or a few others.  By market, I am referring to trading pair.  With alt coins you will find it very difficult to impossible to purchase directly with USD or government backed currency.

Changelly is the easiest way to acquire alt coins out there.  Plus, they have a best in class selections of alt coins to choose from.  Great service guys, this business model is exactly what the crypto space needs right now.