Compare the same model, condition and included accessories across offers. A used portable speaker may have a battery that no longer behaves like a new one, so test charging and playback rather than relying on appearance. Check buttons, ports and Bluetooth connection. Ask who provides support and keep the invoice. A very low price does not explain the product's origin, condition or service arrangements by itself.
Use the live Umoja listings for current price and availability, and verify JBL specifications before choosing a feature-sensitive setup. Your final checklist should include carrying size, listening environment, battery expectations, charging requirements and compatibility with any speaker you already own. Pick the device that serves those requirements consistently. That is a stronger basis for enjoying it than choosing the newest name or loudest shop demonstration.