Don't know where to begin with an asking price? While there are some really good (and somewhat complicated) formulas to use, I am going to give you a starting point.
Obviously, there are many factors to take into account. Such as how long the store has been in business; how long a lease is available, is the store paying a reasonable amount of rent, etc..
Starting point - just to get your thinking is:
Inventory Total +
1 ½
Years Owner's Annual Salary +
1 ½
Years Annual Profit = Asking Price