the 80 minute (~300mb) golds are the old legacy discs... they still will work in the HiMD recorder, but less than 30 mins record time at PCM.
the 1 gig blues will give 94 minutes of record time at PCM.
There was some place on the net that I got a case pretty cheap a few years ago, but ebay prices since then have caught up so you don't have to buy in bulk to get cheap anymore. I'd say $4.50 is a pretty decent price per disc.