Bought the 4G pocket WiFi modem as approved by the Men's Shed group committee last week. Comes with 4 GB of data which expires in two weeks, no chance of using all of that. I've attached it with cable ties to the foot/stand of the Shed's iMac, so it'll be harder to lose & be in close proximity to a USB port for charging. Tomorrow I hope to change the connection to double-sided mounting tape, if I can find any.
I estimate the best data recharge for our usage to be 4GB for $40 with a 60 day expiry. It's a prepaid service, so if we run out, we just renew on the spot.
Doesn't tie us into any contracts.