That's a very good price for both. Can you share with us where you got them?
On the big boat I had AIS that displayed on my PC charting program and found it quite valuable, especially in foggy SF Bay and the California coast. On the little boat I still use the PC charting and after getting to know this area feel it would be a very good addition.
Just a thought to add: If you don't mind (and have a place to put it) having an additional antenna, a simple 1/4 wave whip will do fine and avoid the splitter. It doesn't take much of an antenna for reception of the AIS signal. I made mine using an SO-239 chassis mount connector as the base with four brass rods attached to make the ground plane pointing downward at a 45 deg angle. The antenna element was just another piece of brass rod soldered into a PL-239 connector. Worked just fine!