Many of the tools will come at a high cost. Top ASO tools out there can cost upwards of $10,000 a year. For many app developers, that’s totally unattainable. The benefit of having an agency is that they already have access to leading ASO tools to boost your app. However, many app developers will want to give it their best shot alone, as I do. Try ASObot.pro, its main feature pay-as-you-go scheme. You don't need to spend monthly subscription money. Hope it helps you.