You will pay taxes on any gain realized over your cost basis if sold at a gain. Part of that taxable gain will be the total of all the depreciation you have been required to take for the years it was a rental. In the year you sell, depreciation is recaptured and taxed.
If you sell at a loss, then your losses will be deductible from other ordinary income. But it's doubtful you will see at a loss, even if you sell for less than you paid for it. That's because your cost basis is reduced by the amount of depreciation taken over the years.
