as mentioned, the local market sets the price and condition (how it looks, how rusty and faded the paint is and if the tires are dry rot and cracking) all that can be the most important thing that determines the market price
i will say that husqvarna brand has the best resale value of most mowers
a good used running mower in decent shape with no rust should be somewhere in the selling range of $500
yours has been beat to shit if you broke the frame, not even sure how that is possible even, and then its 12 years old now so i think if you ask $500 you should get it sold, if not take the best offer you get above $300