w-9 taxes/tax forms?

A W-9 is a form that's filled out to request a tax ID number, so I think you're a little mixed up here.

Do you mean that you were classed as an independent contractor, and got a 1099 form from your employer instead of a W-2? If so, that means your employer has not been withholding any taxes for the IRS for the year. That means you should have been setting aside money to pay these taxes yourself. You have to pay taxes on your income no matter how you're classified, it's just a question of whether your employer holds aside some of your money or not.

If you didn't set aside any of your income to pay your taxes, the bad news is you'll have to come up with the money now or make arrangements to pay it off gradually. Your "tax man", if he's any good, should be able to explain all of this to you.

If you are NOT subject to backup withholding, they will withhold zero and you will have to pay the tax either through estimated tax payments or when you file your return. This depends on how much you owe. As you are considered an independent contractor, you WILL owe some tax. If you tell them that you are subject to backup withholding they will withhold at an excessive rate of 38%. You are then likely to get a refund when you file as your total tax shouldn't be more than 30%. Edit: But If I Don't Check "Exempt from backup withholding" and pay the 38% tax, Am I free to spend the earnings I receive? You should be. Your total tax shouldn't be more than 30%, so if they withhold 38%, you *shouldn't* owe any tax and may get a refund. It's hard to tell without knowing how much income you will have. You will have to file a tax return regardless of whether or not they withhold..

That's because they have to file a Sch C. This is a self employed business. Make sure that you deduct expenses related to this income on your Sch C. On this income you have to pay your Federal, State and FICA. FICA is social security and medicare times 2. Because as a self-employed person you pay your portion and the employer's person. As you are self-emploed you pay twice. This is 7.65 x 2 = 15.30% in addition to your Fed and State tax.

Make sure that the tax preparer deducted your mileage or vehicle expenses, and anything that you used to be productive in your work. This will reduce your Sch C income and you will save 15.30% on the portion that you are taking the expenses

1099 worker has to pay self employment tax. I don't know how much you make so it's difficult to tell $5K is reasonable or not.

Your question is too vague, need specifics.