The CGM has been lifechanging for us. However, the most important part was my son seeing how different foods and activities affect him. The second most impactful was the alarms to wake up when he is low at night. These alarms are a mixed blessing however, since sleep gets compromised.
If you were trying to stretch a dollar, get a few used transmitters, have the batteries replaced, and for us each sensor can be stretched to 14-21 days, so you can get by for very little money. If you only ran it for 3 months a year, you would still get most of the benefit for very little cost, i.e. hundreds instead of thousands.
If the battery replacement thing seems too much, then just buy one transmitter and use Xdrip+, you can get almost 6 months out of the G5 transmitter. See @Doc’s results.