[quote name='SonictheHedgehog1337']Is there a limit to the number of coupons you can get at one time? Is there a limit to the number of coupons you can use at one time? Do the trade-in DVDs have to have a case and cover art or can they be disc only?[/QUOTE]
Last time, you could get and use as many as five coupons (one per blu-ray being purchased) at a time. They were pretty liberal about it (at least here), though -- "at a time" meant that you could do five, go out to your car, and come back in with five more and they really didn't care. That will probably vary based on the particular employees that you deal with. Regardless, you can trade in as many titles as you want, you just might have to do it over multiple trips.
I believe that they did require that DVDs have a case and cover art, though I didn't actually try to trade in anything without them, so I can't say for sure.
Of course, that's what they did last time, and they could well make some changes this time based on their experiences from that...