Not sure how long they've been there, but Roku Channel has up 290 episodes of the syndicated version of Deal or No Deal, which is apparently 10 short of the entire series.
They've been there since roughly April. One of my friends, a huge fan of DOND, did the legwork and figured out which 10 Roku skipped over.
-9/8/08 double-run, ep #1011: Noble Jackson
-9/10/08, ep #1043: Stacy Fratelli (This one is, however, on Peacock.)
-9/29/08, ep #1076: Monnae Michaell (This one is also on Peacock.)
-7/13-17/09, eps #1166-1170: The entire Lottery Week. GSN never aired this one, nor is it on Peacock, so unless you taped this first-run you're basically out of luck seeing it again.
-10/1/09, ep #2009: Angela Deeb
-1/18/10, ep #2061: Kymoni Roebuck (the episode that is listed as that date is actually 5/7/10, #2060, with Marty Garcia.)