Hello, I had a question. If I settle if they agree to it, I would receive a 1099 form for about $12,000.. How could I determine how much in taxes I would owe?

Without knowing what other income you have and what deductions and exemptions you are able to claim it's difficult to know.

What tax bracket are you in?

25% I believe. I file single, make about 45-46,000.. own home.

Then you'll pay 25% of the amount in taxes - Federal.

Thank you...

Yes, that amount is just added income to your W2, so if your normal income is 45,000, and you add 12,000 to it.
So look at your taxes you file, what do you normally pay in your income