Today i found two coupon codes for DuraSec protectors:

Coupon code for ClearTec is: 7643404248 (€0,75)
Coupon code for HighTec or NanoTec is: 3172588301 (€1,50)

It's not much but it meant free shipping for my Hightec protecor.

I don't have any experience with these protectors but i read some good things about them. And they have them customized for the N900.