Problem
The price of the item inflated on an estimate. This happened due to a dynamic pricing rule applied to the item's category.
Solution
Remove the category item from the dynamic pricing rule.
Change the dynamic pricing rule
Go to the navigation bar and click Pricebook.
In the side menu, click Pricing Builder.
Select the Dynamic Pricing tab.
Find the rule that's causing the price change and click Edit.
On the Base rule screen that opens, click Edit for Applies to.

Look for the category that causes the issue.
Uncheck the checkbox next to the category to remove it from the rule.

Save your changes.
This stops the dynamic pricing rule from changing the price of the item. For more, see Dynamic Pricing Overview.