Just to let those that may be interested know:
I have been on the lookout for spare batteries for my GPSMAP 296 of late. To source the (genuine) article locally would have cost me AUD$115 ea, plus P&H. A very brief Google search turned up
this place (amongst others) that offer replacement batteries for around USD$25 ea. The batteries I've ordered are the 2200mAH batteries -others offer considerably lower capacity batteries for a dollar or two less. P&H from the US was USD$22, with an anticipated arrival time of 7-10 days. In my experience of ordering other articles from the US, they often arrive in well under that.
I've ordered 2 batteries which probably would have cost me close to AUD$250 with P&H delivered if sourced locally, for around AUD$70 total cost, delivered to my door in probably less time than the local product would take.
Worth a look if you're in the market I reckon.