is there a montly fee for the gps units that are on sale everwhere?

Answer 1

GPS receivers, by nature, is not a paid to use service. It is not a private service like satellite radio or satellite TV.
GPS is a satellite navigation receiver whose signals are transmitted by satellites operated by the US gov't. The signals are free for everyone to receive and use. You purchase the receiver from a commercially manufactured GPS receiver retailer, but there should not be a usage fee to receive the satellite signals.
If there were to be a fee, it may be for other related services, such as maps, etc.

Answer 2

I believe the only fee - is when you update your maps
with all the new roads and subdivisions

there is no fee to use

NOW - there are some upscale models that have a lot of bells and whistles - they MAY require a monthly fee -
and list movies - restuarants - etc
BUT

the standard map and go - nope

Answer 3

One other optional fee, besides map updates, is for live traffic updates that alert you of construction and accidents. Some higher end models offer a free trial period, but after that you have to pay. This is optional though.

Answer 4

No fee, just the cost of the GPS and updates