We have found that most domestic beers in WDW are about $5 per beer in the parks, and the bottles are the 16 oz variety. Much will depend on the brand, but expect to pay a premium price, no matter the brand.
mmmm beer . . . sorry, just had a Homer Simpson moment . . .
alcoholic beverages at Disney parks and restaurants are not cheap.
I know this is digressing, but the Rose and Crown British pub at the UK/Epcot has a 5 beer sampler served in mini glasses for @10.00 ... it's a nice time-out for two people.