sat navs

[maddog04]

looking at getting one for the car but then I thought, could I use it on the bike instead of a bike satnav?
bike sat navs seem more expensive than car ones (another rip off for bikers)
so the question of the day is: have any of you bought or used a (cheap) car satnav and modded it or just attached it to the bike and its performed (given you have a power source plug in)?

[fazersharp]

Waterproof ???=extra cost

[stevierst]

I use my phone for sat nav and put it in a waterproof case. I listen to it on  a cheap Chinese Bluetooth headset. You can switch the sat nav off then and listen to music. Just as good in my experience.