For a 500K deal, can we do all the due diligence ourselves?

At any deal size you would want to bring in 3rd party advisors/consultants. QofE is important, but commercial diligence is even more critical because you want to make sure the quality of revenue can absorb any downside / potential shifts post close, assuming there's relatively small EBITDA.

A good topic of debate with both side representing here. Bringing on the right team to give you confidence that what you’re buying is quality is extremely beneficial. They can also uncover opportunities for strengthening the company’s accounting processes and systems post-acquisition. Keep in mind, there are ranges of QoE—lighter touch/lower $ for smaller, less complex deals (as your question would suggest) to more in-depth analysis/higher $$ for larger, more complex deals. In my experience, a great CPA ought to work with you to match up pricing to scope vs. a one-size fits all contract. Think in terms of a taking a risk-adjusted approach. Good luck!