They are for sale, for cheap, in every drug store.
The number of presumably Europeans in here citing screens blocking light as a reason for not installing screens makes me think maybe those screens are pretty low quality?
They are low-quality in that they tear pretty easily, you need to replace them every 3-4 years or if a bird/cat goes nuts on them (5 eur or so per sqm, probably there are cheaper brands if you are price-sensitive), but they don't block any more light than screens in the US. Less than some I've had.