Google earth, its free, you can mark your stands and see all things from above!
unless you have hundreds or thousands of acre's
I honesty think you can get by without one, and then its one less thing to have to carry with you, or have to keep battery;s in or??
simple reflective markers make getting in and out easy in the dark if needed? way cheaper than a GPS
Sorry if this isn't what you want to hear<
just my honest opinion for you?