You can also check out websites for larger auction houses like Heritage and Great Collections. Look at the professionally graded coins and get a better understanding of the grades and look of coins.
ebay is a tough place to start collecting coins from. I've collected since the mid-eighties and have bought 3 coins on
ebay and 2 of them were professionally graded.
On
ebay, if it looks too good to be true, it is. Once you learn and specialize in a specific area you can cherrypick, but even that is a challenge for most.