Hey Tweetie, welcome to the DISboards.
The best discounts will depend on the type of tickets you want.
For WDW Park Hoppers (with no pluses), the best price will be at your local
Disney Store. There's a discount off the gate price for the advance purchase and by buying at TDS, you will not pay for shipping. If there is no TDS near you, then the second best prices for PHs would be at disney.com. Just be aware that the prices do not include shipping or tax, which will be added on to the total price at the end of your order.
For PHPs (Park Hopper Pluses), the best deal can change from one day to the next. You can check the various online ticket brokers for their prices. Don't forget to factor in the cost of tax and shipping. Many of them will include the tax in their price but some don't. Some charge as much as $11 to ship the tickets and some will ship for free.
My Favorite Sites are:
Ticketmania
Paramount Travel
OrlandoTicketSales
and
FloridaOrlando Tickets
You can also find pretty good prices at
AAA, if you're a member and at Hotwire Savings Club or Connections123.com. All of these require a paid membership in order to purchase the passes at the reduced price.