Hello,
I am working and living in Kabul now. The safe areas in Kabul is Taimani, Shahre Naw, Qalae Fathullah etc. Rent price was very high a few years ago and now going down. Apartments can be rented stating from 300 USD and more. You can rent a nice 2 or 3 rooms apartment.
Other good places for living are Herat in a west and Mazar in a North. These cities are quite big and security is quite good there.
Property tax s nothing. If you rent house or apartment owner will pay all taxes. Rent houses much expensive than apartment but still you can find house starting from 500$.
If you buy apartment stats from 30,000$ depending on area, houses starts from 60-70 thousands dollars. Houses and apartments are expensive in a safe areas, in a center and cheaper in suburbs. Living conditions not bad but also not perfect, you must invest money for the good life.
Best regards,
Fozil