The genesis of any organizational initiative is often the recognition of a need. For those navigating the competitive landscape of talent acquisition, the need to streamline hiring processes via an Applicant Tracking System (ATS) can hardly be overstated. However, despite the apparent benefits of investing in an ATS, it is vital to plan and budget effectively to ensure its successful implementation.

An ATS is a sophisticated software application that facilitates electronic handling of recruitment needs. It simplifies the process of sorting through resumes, tracking interactions with candidates, reducing bias in hiring, and improving overall efficiency. However, it is not a one-size-fits-all solution and requires careful financial planning and strategy.

The first step towards effective budgeting for an ATS is an in-depth understanding of your organization’s specific needs. This in itself is a multifaceted process, necessitating a comprehension of your hiring volume and frequency, the complexity of roles, and even the geographical spread of potential candidates. Establishing a clear-headed view of what you expect from your ATS would help you better evaluate the cost-benefit analysis of this investment.

Next, the selection of the ATS should be based on the technical specifications and features it offers. Some organizations may need a system with advanced AI capabilities, while others might be satisfied with a more straightforward, manual system. The sophistication of technology will directly influence the cost of the ATS. Therefore, it's crucial to map out your requirements vis-a-vis the features offered by the ATS to ensure you are not overpaying for superfluous functionalities.

An often overlooked but critical aspect of budgeting for an ATS is considering ongoing costs. These could include maintenance, upgrades, user training, and potential downtime costs. From an economic perspective, these can be categorized as the 'opportunity costs' of the system. It's crucial to factor these into your budget to prevent any unpleasant surprises in the future.

In the realm of behavioral economics, the concept of 'sunk cost fallacy' may also come into play when budgeting for an ATS. This economic theory dictates that individuals often continue investing in a decision simply because they have previously invested resources into it, despite clear evidence that the decision may not be beneficial. Hence, it's important that the organization does not get trapped into investing in an ATS simply because they have spent considerable time and resources into its research. If the system is not serving its purpose or proving too costly, organizations should be ready to pivot and explore other options.

Beyond pure economics and finance, legal considerations can also impact the budget. Legal compliance in hiring processes is non-negotiable, and your ATS should aid, not hinder, this. Ensuring your ATS aligns with laws like the Americans with Disabilities Act or data privacy regulations can incur additional costs but are crucial to prevent potential legal disputes.

Lastly, it's important to remember that the implementation of an ATS is not a static, but a dynamic process. The world of recruitment is constantly evolving, and your ATS must adapt to these changes. Thus, a portion of your budget should be allocated for future updates and potential system overhauls.

In conclusion, budgeting effectively for an ATS involves a comprehensive understanding of your organization's needs, careful selection of system based on technical specifications, accounting for ongoing costs, avoiding the 'sunk cost fallacy,' considering legal aspects, and preparing for future updates. By combining these strategies, organizations can ensure that their investment in an ATS yields desired results without causing financial strain.