Depending on on what phone you have, and how you use and load maps, determines how much data is used. The other thread shows just how much data it is possible to use.
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Does my use of the GOS function on the phone count towards my data plan? I can use my old phone without a SIM card on GPS no problem.
As @lizdance40 has mentioned, the GPS feature of your phone itself will not use any cellular data. What uses the cellular data are all the apps that make that GPS feature something useful for you. I have my old iPhone 5 that I use for some location based games, and it works fine without a cellular connection at all, it just can't get any data from the internet that it doesn't already have loaded. Almost all the apps that use the GPS for anything useful also use the internet to download maps & other data so you get the "most up to date information". Those apps do tend to use a good bit of cellular data to do that though.