What is the best way to fund Uniswap besides ETH?

I’m located in the US, so many Altcoins are not on our Exchanges. When I purchase non-listed tokens I’m required to deposit something to make the swap. The only thing I know to do is purchase ETH and move it to Uniswap. Ultimately I guess it doesn’t matter, but I have to buy ETH on some exchange and hold it for 10 days before I can move it. It sucks because I’m selling ETH bought at $200 and replacing it with ETH at $380. Like I said, I guess it’s a wash in the end, but I have to believe there is another way to fund Uniswap/Metamask to buy altcoins.

On a related topic, where can I purchase non-ERC20 tokens in the US? They are not available on Uniswap.