Around $100 is a starting place. I've seen current Leander homes sales vary from $63 to $119 a square foot.
Like many agents, I would be happy to meet with you, view your home, and do the research to make a well considered Comparative Market Analysis (CMA) at no cost to you.
Since Texas is a no-disclosure state, only licensed real estate agents and brokers have access to the information on sales price to arrive at a well informed analysis.
An analysis that goes by the asking prices only tells you what the current competition is, not what the selling market prices in your area are.
I specialize in Leander, so have some insights into the specific neighborhood markets.