What exactly is the "property" that was sold? What was it used for? How long did you own it? In what year did you sell it?
Additional questions added after initial post:
How did you acquire the property that you sold?
Is anyone else involved? Are you single or married? Were you the only owner of the property that you sold?
Depending on the details, if you sold something for $300,000, you probably do not have to pay tax on the entire $300,000 selling price. You pay tax on your profit from the sale, not on the full selling price. How the taxable profit is calculated depends on the details. If the property was your personal main home, and you owned and lived in it for at least two years before the sale, you might not have to pay any tax at all.
We will be able to give you specific advice when we have more details.
