A customer is mailing a heavy package within the US. They want the cheapest option. What service consideration is MOST important to discuss?

USPS domestic service options for heavy packages include: (1) PRIORITY MAIL EXPRESS — fastest (1-2 days), most expensive, money-back guarantee, insurance up to $100 included; (2) PRIORITY MAIL — 1-3 days, cost based on zone and weight (or flat-rate options independent of weight up to limit), tracking and insurance included up to $100; PRIORITY MAIL FLAT RATE BOXES are a major selling point for heavy items going far — same price regardless of weight (up to 70 lbs) and destination zone, dimensional limits apply; (3) USPS GROUND ADVANTAGE — successor to First Class Package Service and Retail Ground, 2-5 days, cost-effective for packages 1-70 lbs, tracking included; (4) MEDIA MAIL — for books, sound recordings, recorded video; very cheap but content-restricted, slow; (5) BOUND PRINTED MATTER — for catalogs and bound printed material; restricted, slow, cheap. For heavy items: Priority Mail Flat Rate Boxes and Ground Advantage are usually cost-competitive. The exam screens for: (1) Service KNOWLEDGE — understanding the menu of options; (2) MATCHING service to customer need (cheap = different than fast); (3) INFORMED choice — present features so customer decides; (4) HONESTY — don't push expensive options or refer to competitors. Recommending USPS Ground Advantage or Flat Rate Priority for heavy items is usually the right answer for 'cheapest with reasonable delivery.'