What is the Best Way to Buy Concert Tickets?

I have found that the only way I ever seem to be able to get tickets for the concerts that I want is to search for them online, but I am not sure I am ending up getting them for the best price. Can anyone tell me which is the best way to buy premium tickets for concerts online? Are there some websites that tend to always have tickets, or to have tickets for less than some of the other websites out there? I don’t want to have to search a whole bunch of websites before buying tickets, but I also don’t want to pay any more than I have to.