I'm in the US as well, so I understand your pain. I think you're asking how to get access to a wide range of coins and not just BTC, ETH, and LTC that Coinbase offers. Right now, your only real way to do this is to purchase coin from Coinbase and then send it to your desired exchange. Then use those to purchase the coin you really want. Since most exchanges leverage BTC as the primary currency, it'd make sense to purchase BTC and then send it to the exchange. As for exchanges, Bittrex is a good one, but others will comment on the many others that are out there.
Yes exactly what I was looking for. I will buy BTC and go about it that way. Does bittrex hold your wallet like coinbase?
Yes, all the exchanges will have '
wallets' to store the coins you purchase, but you'll get a strong reaction from the community about storing your coins on an exchange for an extended period of time. I'd also consider Coinbase an exchange; so keep that in mind.
When you store your coin on an exchange, you're trusting that exchange to remain solvent and not disappear with your coin. Crypto exchanges are not ensured and many of them are not regulated (which I prefer.) The recent shutdown of BTC-e and the recent stability/communication problems from Poloniex definitely lends credence to that concern. Just read this article for more info. Bottom line; purchase BTC from Coinbase, move to an exchange to purchase the alt-coins you want, and if you plan to hold them, move them to an official wallet for ultimate security.
https://steemit.com/cryptocurrency/@fraenk/psa-don-t-leave-your-money-on-an-exchange-btc-e-is-offline-an-admin-is-suspected-to-have-been-arrested
