I bought an annual policy from Cover4Rentals, as I've a few rentals coming up in a short period of time. €53 for their 'Gold' level.
On a related note - has anyone ever had to make a claim on an Excess Insurance policy? Do they make it more hassle than it's worth, documentation wise etc.? I rented last week in the UK, and due to narrow country roads and lots of briars, the car got loads of light scratches. As I had the excess insurance, I should have just handed the car back to the company and claimed back whatever excess they charged me. But fearing a potential headache, I thought it easier to spend £15 on some T-cut and polishing pads to buff the scratches out!
I think many of us have a fear of claiming on motor-based insurance policies for fear of losing our no claims record!