I do recommend buy those PDA with GPS antenna, and just purchase the GPS software from Navman or other brand, then you will have a GPS system plus a fully function PDA and total cost should be <$1000. I bought my PDA in HK $400 and a Navman program on ebay for $300. For accuracy, i can say its only +/- 10m, but only when u travel legal speed. For me, as my average speed is 80km in the city, it always notify me to turn when i just pass that corner <_< But anyway, its really worth to have 1.