honestly, will cost you less than most of the other alternatives, even considering buying the iPhone. The phone will cost you $200 for a nice new one (with ATT contract) or about $200 for a used one (no contract). The entire east coast is just $10 from Navionics, and you get the same chart that goes on a Raymarine plotter. If you buy the new phone it will be the 3GS with GPS built it. A used 3GS will cost more, a 3G or earlier phone doesn't have the GPS (charts still work though).