Use the cost of the mower (or any asset) plus the sales tax when determining the $2500 rule.
If it doesn't qualify for the rule, you can still claim a Sec 179 deduction which would have a similar "expense" effect. If you have any other details regarding this question, please feel free to post them in the comment section.
Instead of depreciating an asset over a multi-year period, you might be able to deduct its entire cost during the first year of use. This is called a Section 179 deduction, also (erroneously) called Section 179 depreciation. Think of it as instant gratification when it comes to deducting the cost of a newly-purchased business asset.
To enter a Section 179 asset:
1. Select the Federal Taxes tab, and then click Deductions right below it.
2. Click the Start or Edit button to the right of Assets.
3. Follow the on-screen instructions. When you get to the How Do You Want to Deduct this Item? screen, select Deduct all or part of the item's value this year.
4. Enter the amount of Section 179 deduction you want to claim for the asset. Do not exceed the cost of the asset
