There are many ways of getting Philadelphia Flyers tickets. Primary ticket sellers, which include the Flyers themselves and Ticketmaster, usually have game tickets. The upside is that the prices are usually good, but the downside is that the best seats may no longer be available.

Another choice is buying from a secondary ticket broker. They buy up spare tickets and resell them for a higher price. When they hawk them outside the stadium, they're called scalpers, but many brokers run legitimate businesses from offices across the country. The prices may be a bit higher, but the choice of seats is usually better than anywhere else, even official channels.

All of my purchases from brokers have turned out fine. I like brokers because they sell the tickets to those who are willing to pay the most for them, rather than whoever asks them first. I prefer to pay more in order to sit right up close. Some of the better broker websites I've found for Philadelphia Flyers tickets are:
TicketLiquidator.com
Ebay.com
Stubhub.com
Hailstorm.com

There are also some tickets available in classified ads. Getting Philadelphia Flyers tickets directly from a person is risky because there are not the same security measures in place as there are for primary or secondary sellers. That said, you may be able to get a good deal, particularly just before the game happens. Some good classified listings are:
Craigslist.org
USTBA.com

To summarize, if you just want to get in to the game, primary sellers like the Philadelphia Flyers or Ticketmaster are the way to go. For better seats, brokers like TicketLiquidator or Ebay can't be beat. Go Flyers!