Good to hear from you again.
78717 isn't really North Austin. That zipcode encompasses the area North of 45, West of Great Oaks, South of Brushy Creek and East of 183. Most identify it as Cedar Park South or West Round Rock. The vast majority of homes currently for sale (170) are priced above $200K. Of those, only about 16 are priced at $200K or less. Those are concentrated in Avery Ranch West and Far West, or Brushy Creek.
What I would concentrate on is not zipcode, but the elementary school. Look for those with the best ratings in the areas of town you're willing to live. For example, Fern Bluff, Great Oaks, Cactus Ranch and Brushy Creek elementary schools were all rated Exemplary. These are located in 78681. Same for Jollyville Elementary in 78729, Spicewood Elementary in 78750, Ada Mae Faubion Elementary and Deer Creek in 78613.
But again, don't concentrate on zipcode, focus on the better elementary schools in your search. Let me know when you get closer to wanting to setup some customized searches. I can setup your own website and have the searches automatically update for you if you'd like.