The verdict
If you are not yet running paid search, pick Google Ads and nothing else. Set up conversion tracking first, make sure you have a landing page that converts, and test with a small budget.
If you already spend steadily and one person manages several accounts, add Adalysis. The hunt for wasted spend moves from spreadsheets to a daily list of findings. A long free trial lets you see the findings on your own accounts first.
I would not buy Adalysis for one small account. You can check that by eye, and the tool only helps if someone acts on the alerts.