Also, you may want to browse ryokans for their details, locations, etc with the link in this post.

IMHO JPY7000-10000 in Kyoto would be enough for standard ryokan (with dinner and breakfast incl) if you'd like a simple but decent room. Not fancy, though.

Edited to add:
If you're on a budget but still want to try good ryokan and everything, why don't you save by staying at hostels like Uno House or Cheapest Inn, then try the superb ryokan for the last few days?