I'd try to knock him or her down some, perhaps. I too don't know anything much about Sealife products from personal experience, so not giving you any advice on that front. I'm just a fan of using eBay as a bit of indicator of average used prices. There'll be the occasional outlier on both the cheap and the costly side, but you'll get some idea of the right range at least.
My best customers bought SeaLife and then they came to see me later... ;-)
i'd look around for a decent Canon or a Fuji in a case. I've seen FXF-200s and a Fuji case for about that.
But gees with 2 bodies how many spares do you need?