Went to Camping World, St. Augustine today to buy a new Overdrive 7 GPS. The store had what I wanted but it was locked in a cage with all the other electronics, plus some of the other high priced item...
I use a Generic I got at eBay for $50. Has a bus setting and it's been very reliable telling me where to go...as regards roads a big bus can take.
Not sure if you're a Camping World member but the good prices they usually advertise are only for members so keep that in mind. I didn't ever buy enough for their membership to be economical so only had it for one year. The 4X per month ad fliers from them via snail mail were not appreciated either.