It wasn’t covered by insurance, but the Freestyle Libre CGM was $37 at CVS & lasts for 2 weeks. The major cost factor (for most people) is getting a doctor to write you an Rx.

Levels is around $400, but all you have to do is fill out a form online & wait. They get a doctor to evaluate your profile & write an Rx, and then they fill the prescription & send it to you with patches & everything. Their app also does more data analysis than the default Libre app, and it puts the food-log directly on the glucose graph, which is surprisingly useful.