With regard to Motorola (from Wikipedia - they have a chart to identify your phone- I have to see what one I have):I wonder how hard it would be to find a network that would be willing to service one of those things? They were pre-SIM cards, so how would a network even find it?
Obsolescence
The majority of Bag Phones operated on the AMPS network, and a few special models produced in the late 1990s, dubbed the Digital Concert Series, ran on the TDMA network, in addition to AMPS. Because both the AMPS and TDMA networks are extinct as of February 2008,[2] the service life of all Motorola Bag Phones have come to end, and they now serve only as a collector's item.The original Motorola Bag Phone has been succeeded by the Motorola M800 and M900 Bag Phones, introduced in 2005. While they are technologically dissimilar to the original Bag Phones and use an entirely different user interface, the M800 and M900 support CDMA and GSM, respectively, and add the basic features of modern cell phones. Additionally, they are backwards compatible with batteries for the original Bag Phones.