I had it for almost a year and a half a few years ago. I tried all the stuff....insoles, rolling on frozen water bottles, ibuprofen, etc.... My wife read in a runners' magazine that wearing flip flops is great rehab for plantar fasciitis. We were in Hawaii at the time. She bought me some flip flops in the hotel store. I wore them all week, even though I'd always HATED flip flops all my life. Couldn't stand to have anything between my toes. Anyhow, by the time we got home, my foot felt almost back to normal. I kept wearing the flip flops as much as possible - even to the office a few days that first week back. In a couple more weeks' time I was healed up.
When you wear flip flops, you have to kinda use your toes to grab and hang on to the shoes while you walk to keep them from flying off your feet. That little flexing of the bottom of your foot (plantar fascia) while you walk with them is apparently good exercise. It strengthened the tendon, I guess. And it healed up. All the other stuff I'd been trying was the opposite. Everything else was resting and babying it, rather than strengthening it.
Now I wear flip flops a good bit (not during winter). I haven't had an issue with PF since.