That is one of the most difficult questions to answer without seeing the instrument. It is like asking what a car is worth sight unseen. Especially with an older piano. It varies considerably with things such as, how often has this piano been tuned? Who was the tuner. Believe it or not but, there is a world of difference between one tuner and the next. There is also a world of difference between the piano that has been tuned yearly and those that have been tuned every 10 years or longer.
Everyone thinks their particular piano is in marvelous condition because they have dusted and polished it. Especially when the outside looks nice. However, as piano technicians, the piano is judged mostly by the insides. That, is what matters most.
Without seeing the piano, it is impossible to give an honest opinion. It could be worth $50, or $2,000. Again, depending on the previous care along with the location of the piano. Hire a good technician in your area to look at it. They will be your best bet for answering this question in full.