It depends on what you paid, how much work you may have put in, any write off you may have taken, your tax bracket, etc.
Here is a basic example, assume that you paid $120k and have taken a tax depreciation of $4363 each year for 5 years. With this, your tax base would be about $97k, so you would pay a long term capital gain of 15% (or less, depending on your tax bracket) on the difference between $183,511 and the $97k.
You can also take other deductions to help reduce the gain, but that is the general idea.
Talk to a tax professional to get a more details.