Black Friday was the time to get one, Circuit City and RadioShack had the biggest, nicest models out of anywhere (~$100-$120 for 10+inches).
I'm guessing this Black Friday will follow suit ($49 for the cheapest ones)
Coincidentally, tonight only (until Wednesday at 11:59pm central time or whenever they sell out) Woot.com has a 10.2" wifi frame for $129.99 + $5 shipping.
One thing I've read up on with digital frames: if it's too widescreen you may have to format all of your pictures to fit properly without it automatically stretching out to fit the funky size. I'll be on the lookout for a moderately priced not-too-widescreen one this year for BF.