As of now, You cannot buy an Ethereum coin as you would with Bitcoin. The only way to acquire Ether is by mining for it or purchasing it with fiat currency on an exchange.
While there are plans to release physical coins, as of now there are no official Ethereum coins.
The Ethereum network is still in its early stages, and the team is still working on releasing a number of features. Once the network is more developed, we may see Ethereum coins being released to the public.
Until then, the only way to acquire Ether is through mining or purchasing it on an exchange.