At 80 how much income above SS can you make before you have to file a return?

I think that you mean how much income can you earn before your Social Security income is taxable. Age is not a factor of whether your Social Security is taxable, total income is. Social security income becomes taxable when your other income plus half of your social security exceeds an amount based on your filing status ($32000 if you filed jointly). Initially, only 50% of your benefit above a certain threshold is taxable. When you exceed the first threshold, up to a maximum of 85% of your benefit can be taxed at your income tax rate. But even if your Social Security is not taxable at all, you should file for 2007 to be sure that you receive a "stimulus package" tax rebate.

For 2008, single, over 65, it's around $10,000

On a joint return, $19,600 if both spouses are over 65. If it's not a joint return, $10,500 for 2007.