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Tools / Buying a business

Tool collection · Buyer OS + seven companion applications

The Verified Acquisition System.

Keep the buying process in view, and open the right tool for each decision. Buyer OS connects the journey; seven companion applications help you work through the numbers, offer, diligence, and financing.

Buy the complete system — $29 ↗

One-time purchase · All eight applications · No subscription

Personal or one-organization use. Team and paid client work included; share completed work. Reusable product distribution requires separate permission. Read the product license

Follow an example purchase
A journey illustration. Revisit stages as the deal changes.
What to bring
Your buyer mission, a specific opportunity, deal figures and investigation notes. Each application asks for the information relevant to its decision.
What you keep
Buyer OS, four calculation tools and three document and diligence tools. All eight are included in the $29 package.
Keeping & returning
Each application has its own outputs and saving behavior. Buyer OS links to the tools; entries do not automatically transfer between them.
Reading, related tools & help

Read the guide

Start with the business. And the life around it.

Begin with the work, preparation and investigation involved in buying.

Choose related work

Find outside help

Find relevant people & guidance

Find learning and outside help alongside your own acquisition work.

Extract the complete ZIP and open Buyer OS in a modern desktop browser. The eight applications run offline; no Excel, installation or product account is required.

ZIP download · Runs offline in a desktop browser.

30-day money-back guarantee. Free updates.

For the guided application on its own, explore Buyer OS — $9. You can also start with the free Buyer Brief.

Know what you are getting.

Which part does what?

Choose an application to see the job it supports, the information it needs, and how you can keep its output. All eight are included in the package.

The guided workspace

Buyer OS

Work through the decision stages and record the questions, evidence, and decisions around a particular opportunity.

You bring
Your buyer mission, deal information, investigation notes, and decisions.
You can prepare
A deal journal and a one-page deal summary, with links to the included tools.
Keep your work
Copy the deal summary or print/save a report. The OS also uses browser-local state.

This is a guide to the package contents. The purchased applications are separate files, not embedded demos here.

For a particular opportunity.

The package helps you organize information and examine your assumptions. Its calculations depend on the information you enter. A generated document or result still needs appropriate review before you act on it.

Still deciding what to look for?

Start with the free buyer-preparation worksheet. It helps you describe the work, boundaries, and questions that will shape your search.

Opening it. Using it. Keeping your work.

How do delivery, updates and refunds work?

Checkout and the ZIP download are provided through Gumroad. Keep your purchase receipt for access to your download and support. This package includes free updates and a 30-day money-back guarantee. Reply to your Gumroad receipt to request help or a refund.

Read the delivery and refund details, or visit Contact & Support for help finding your receipt.

What do I open after downloading?

Extract the whole ZIP. Inside the main-street-buyer-os folder, open product-15-buyer-operating-system.html. Keep that file, README.txt, and the tools folder together. The included tools open as separate local applications.

The applications run offline without Excel, installation, a product login, or a cloud account. Use a modern desktop browser; the downloaded Buyer OS opens all seven companion tools from the extracted folder.

Do the applications share my deal information?

No. Buyer OS links to the included tools, but each application keeps its own entries where storage is supported. There is no automatic exchange of deal data between the apps and no shared cloud workspace.

How do I keep or move my records?

Buyer OS provides a copyable deal summary and printable reports. Deal Sizer, Payment Lab, Max Purchase Price, and Valuation & Offer Builder provide copyable summaries or memos; they do not keep browser-local deal files.

Loan Package Builder, Due-Diligence Deal Room, and LOI & Offer Builder provide JSON export/import and print controls. Export includes a download link and selectable JSON text if automatic downloading is blocked. Keep an exported file for restoring work in the same application. Moving files, changing browsers, or clearing browser data can make browser-local entries unavailable.

Are the seven tools separate purchases?

All seven tools and Buyer OS are included in this $29 package. They are also offered individually. If you buy the complete system, you do not need to purchase any of these eight applications again.

Purchase and delivery. Checkout and the ZIP download are provided through Gumroad. The package contains eight separate applications; entries do not automatically transfer between them.

The system in use / Fictional example

One purchase. Different questions.

Riley is considering Harbor Cycle & Repair. Follow the questions, the tools, and the decisions to record.

01 / Is this worth investigating?

A busy workshop.
A first set of numbers.

The broker sends asking price and reported earnings. Riley wants to know whether the rough financing and cash required fit before spending weeks on the deal.

Open Deal Sizer

Enter the asking price, earnings, available cash, closing costs, and financing assumptions. Compare scenarios and keep the deal memo.

Leave with: an initial financing scenario

Record it in Buyer OS

Write down the buyer’s limits, which figures are still unverified, and the next seller questions. A promising model is a reason to investigate.

Leave with: a next step and open questions

Illustrated use case, not an application screenshot. Eight separate offline apps; entries do not automatically transfer.

Keep your open draft?

Continuing will discard your unsaved changes. You can return to the draft and save or download it first.

Inside a real tool

The Cash Timing Planner

A screenshot from the working planner, using fictional figures. This example starts with $2,000, reaches a low of $300, and ends the eight weeks at $900.

Swipe across the preview to read the details.

Eight-week cash balance chart from October 1 to November 25, 2026. The lowest balance is $300; the expected end balance is $900. The dotted line marks the example's chosen $500 cash level.

The full tool lets you enter receipts and payments, try a change, and keep an editable copy.