If you don't drive much and you drively safely, you may be able to save up to 30% on your auto insurance premium with Progressive Snapshot. This BusinessWeek article
describes a new announcement from Progressive which lets anyone try Snapshot for 30 days for free.
I don't think 30% is enough for low-mileage and safe drivers. A small insurer in Texas, MileMeter, used to offer bigger savings for low-mileage drivers. However, it looks like their business model had problems. MileMeter no longer exists
as an auto insurance company.