CartrouteHow often does shipping change which retailer is cheapest?
In the Cartroute catalog on September 23, 2026, the retailer with the lowest sticker price was not the cheapest once shipping was added on 0 of 40 products (0%). Adding the best available coupon raised that to 8 (20%).
How big is the price gap between retailers for the same product?
The average spread between the highest and lowest listed price for an identical product was $164.28 across 40 products. The widest was $703.00 on the Samsung S95F 65" QD-OLED 4K Smart TV (2026).
Which products flip when shipping and coupons are counted?
| Product | Lowest sticker | Pays | Actually cheapest | Pays |
|---|---|---|---|---|
| Apple MacBook Air 13" (M4, 16GB RAM, 256GB SSD) | Best Buy $863.99 | $863.99 | Costco $918.99 | $843.99 |
| Dell XPS 14 9450 (Core Ultra 7, 16GB, 512GB, RTX 4050) | Micro Center $1,616.99 | $1,616.99 | Costco $1,622.99 | $1,547.99 |
| TCL QM8 75" QD-Mini LED 4K Smart TV | Target $1,778.99 | $1,778.99 | Costco $1,847.99 | $1,772.99 |
| Breville Barista Express Impress Espresso Machine | Sam's Club $817.99 | $817.99 | Target $905.99 | $724.79 |
| Vitamix A3500 Ascent Series Smart Blender | Walmart $616.99 | $542.95 | Target $659.99 | $527.99 |
Which kinds of product are most affected by shipping?
Heavy and bulky items. Freight on adjustable dumbbells and delivery on major appliances run from $50 to $100 at some retailers and nothing at others, which is larger than most price differences in those categories. Small electronics under a retailer's free-shipping threshold are the other common case: a $5.99 shipping charge on a $30 accessory outweighs a $3 price advantage.
What should an agent do with this?
Compare on effective_price_usd, never on price_usd. If the shopper has no Costco or Sam's Club membership, pass include_membership=false so a members-only offer does not win. Check best_coupon.requires_code and pass the code to the shopper when it is true.