Maximum Buy Price: Work Backward From the Exit

A deal should remain attractive after normal friction, not only if everything goes perfectly.

The maximum buy price is the number that protects you from negotiating your way out of the profit. Start with realistic target sale price, not list price. Subtract known selling costs, transport, missing accessories, expected repair/cleaning, payment fees if relevant, and any other direct cost you consistently count. Then subtract the profit you require for the time and risk. Finally subtract an uncertainty buffer when condition, selling time, or market value is not fully known. A simple version is: Maximum Buy Price = Target Sale Price - Direct Costs - Desired Profit - Risk Buffer. The exact categories inside 'direct costs' depend on the deal. For a local cash sale, there may be no platform fee. For a shipped purchase from another country, shipping, tax, duty, brokerage, exchange rate, or buyer premium may matter. This is why the sticker purchase price is not always the real cost. Suppose target sale is $1,100. You expect $30 of travel/accessory cost, want $150 profit, and keep a $50 uncertainty buffer. Maximum buy is $870. If you pay $950 because the seller is persuasive, you have effectively spent most of your safety margin before the item even becomes yours. The risk buffer should reflect the quality of your information. If the item is fully tested and local market value is stable, the buffer can be smaller. If you are buying a lot of untested units, the buffer should be much larger. Do not worship a fixed ROI percentage. A 30% ROI on a $100 item may only be $30 and not worth your time. A lower percentage on a fast-moving $2,000 unit may still create excellent dollar profit. Use both percentage and dollar profit together.

You can calculate a purchase ceiling before messaging a seller.