DVC members only get a discount on the LOS ticket at the time you check in to the resort. Discout is 10%. Any other tickets you might want to checkout Mousesavers.com As of the recent price increase your best savings will be on tickets you buy in advance.
Here is a link to <a href="http://www.wdwinfo.com/wdwinfo/tickets.htm">WDW Ticket Prices</a> right here on the DIS.
Just find the number of days for your stay and be sure to deduct the 10% DVC Member's discount from the price. These cannot be purchased in advance, but will be encoded on your room id at the resort. You can also usually drop first and/or last day from the number you'll need (if you'll arrive late in the day or depart early you can drop those days from the number on the pass).
LOS = Length of Stay and was one of the early names for what is now called the UPH pass. It is the only pass eligible for the DVC discount and includes admission to all Disney Theme Parks, Water Parks, Pleasure Island and Disney Quest for every day of your stay- including arrival and departure day- unless you ask for those to be dropped (for a lower rate).
Instead of buying Disney's Ultimate Park Hopper, priced at $418 adult, there is a pass called Fun in the Sun available from Paramount International. Adult price is $311 and is valid for 30 consecutive days.