Thanks hns.

Really, the conditions aren't all that bad. I already have an A1 contract, so I could buy it for €269,- (!) (minus € 20,- if I buy online, so the actual price is € 249,-).

I need to use 11.500 of my bonus points for this (no problem with that) plus take one of several possible add-ons. I would choose a data plan instead of the navigation thingie, so that would be a 24-month-contract for € 10/month.

Having this data plan is probably a good thing, anyway, if you own the N900. So if I calculate it that way (=data plan doesn't count because I'd pay for it anyway), it's really only €249.