What is retail arbitrage?

The in-store version: sourcing clearance products from physical shops.

Retail arbitrage (RA) is the physical-store version of the same flip: walking clearance aisles with a barcode scanner, buying discounted stock and reselling it on Amazon. It is many sellers' first step because the starting budget can be tiny and the feedback is immediate.

Its limits are geography and hours - you can only scan the shelves you can reach. Online arbitrage removes both by sourcing from retailers' websites instead, which is why most RA sellers eventually add or switch to OA as they scale.