if Plenio VXA-2100 7-inch GPS Navigation System is a good system. Does it say the name of the street you must turn on by voice command? Would you recommend it? If not, do you know of a Plenio VXA-2100 7 inch GPS system and where you can buy it for about $300
That really depend on the software modern softwares will not tell you the name of the street it will say on the first,second street to turn left or right and it will tell …

does the itouch has gps system and how does it works?
Itouch do not have gps navigation system this time. but have another gps navigation funtions with itouch, You can call up google maps via the web browser, it will not show you where you are located, you would have to center the map on your location.
In the future, after the development kit is released, someone could write an interface to a bluetooth GPS for itouch.