Identify each role
Seller, payment processor, warehouse/fulfillment provider and marketplace may be different organizations.
Check which policy applies
Returns, warranty handling and shipping promises can differ by seller even on the same marketplace.
Compare delivered cost
A lower item price can be offset by shipping, import charges or less convenient returns.
Keep seller identity with your records
Screenshots or confirmations help if the marketplace listing changes after purchase.
General educational information only. Consumer rights, tax treatment, warranty obligations and return remedies vary by seller, product and jurisdiction. Use the actual contract/policy and current official consumer guidance where rights matter.