The minilink system from Medtronics is just under $1000 for the starter pack (I think the Dexcom is about the same). That includes the transmitter and 10 sensors (if you don’t have a minimed pump, which serves as a receiver, then I think you’ll need to pay more for a separate receiver). Replacement sensors cost $35/each. I’m averaging about 7-day use for each sensor, though I expect that to increase now that I’m over my learning curve (I removed 2 sensors earlier than needed and have gotten up to 14 days out of others). So 10 weeks after the initial purchase, it will cost around $140/month for continuous use. The transmitter has a rechargeable battery that will probably require replacement in a year or two, so that’s an unknown cost at this time.
I use mine almost all the time, though I sometimes choose to go a day or two without it in between sensor changes. Using only 2 sensors each month (50% of the time), would still be very helpful at detecting patterns and helping a person train themselves on how to better regulate things. I thought I had pretty good control on MDI and 4 glucose tests a day, then I got the pump. I thought I had pretty good control on the pump and 7 - 8 glucose tests a day, then I got the CGM. It’s really amazing what you can learn when you’re able to watch continuous updates of your glucose after a meal, all night, during exercise, etc. I’ve been able to significantly reduce my post breakfast spikes using the CGM.
It’s not perfect and those times when the accuracy isn’t as great as you’d like are frustrating. But overall, I’ve found it very beneficial.