Smart Phones that can capture GNSS, Wifi, Bluetooth signals etc. have dropped substantially in price. Instead of using some custom hardware solution, it is normally cheapest just to get a "supermarket" phone as a data collection device:
If you cannot afford new phones, most second hand phones no more than 5 years old should also be good enough.
Pagers may be cheaper providing a very limited Personal Console but NOT they recommended in locations with cell phone coverage.