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  1. Showing 1 - 36 out of 177 results for "flat rate box sizes"
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      Idl Packaging Flat Corrugated Shipping Boxes 12"L X 12W X 4"H (Pack Of 10) - Excellent Choice Of Strong Packing Boxes For Usps, Ups, Fedex Shipping
      Idl Packaging Flat Corrugated Shippi…
      Walmart
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      Extra Priority Mail Flat Rate Large Shipping Box | Color: Red | Size: M
      Extra Priority Mail Flat Rate Large Shi…
      $10,000.00
      Poshmark
      SALE
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      Priority Mail And Priority Flat Rate Large Box Shipping 1-3 Days
      (5K+)
      Priority Mail And Priority Flat Rate La…
      Etsy
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      Shipping Upgrade To Priority Flat Rate, Small Box
      (1)
      Shipping Upgrade To Priority Flat Rat…
      Etsy
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      DOMESTIC Small Flat Rate Box Priority Mail Upgrade
      (1K+)
      DOMESTIC Small Flat Rate Box Priori…
      Etsy
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      Upgrade Your Shipping To Priority Small Flat Rate Box, Expedited Processing And Rush Order For Made To Order Or Ready To Ship Listings
      Upgrade Your Shipping To Priority S…
      Etsy
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      Upgrade To Priority Mail Flat Rate S…
      Etsy
      delivery truckFree shipping
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      PRIORITY MAIL Shipping Upgrade - F…
      Etsy
      delivery truckFree shipping
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      (24)
      AVIDITI Shipping Boxes Flat 12.125"…
      ($1.13 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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      Medium Flat Rate Box - Random Sch…
      eBay
      Price Drop Green Icon29% DROP
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      SSBM Flat Corrugated Boxes Kraft S…
      Walmart
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      10 Small Flat Rate Boxes
      eBay
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      Lotus By Lina Priority Shipping Upgra…
      Etsy
      delivery truckFree shipping
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      Medium Flat Rate Box - Random Sch…
      US eBay
      delivery truckFree shipping
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      BOX USA Flat Mailer Shipping Boxes …
      ($1.66 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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      (24)
      AVIDITI Shipping Boxes Flat 12.125"…
      Amazon
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      (6)
      SHIP NOW SUPPLY 16 X 16 X 4 Corr…
      ($2.40 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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      Medium And Large Flat Rate USPS B…
      Etsy
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      Medium And Large Flat Rate USPS B…
      Etsy
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      Large Priority Flat Rate Box Of Stuff- …
      eBay
      Price Drop Green Icon95% DROP
      delivery truckFree shipping
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      (1)
      Priority Mail Upgrade, Small Flate Rat…
      Etsy
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      SHIPPING CHARGE ADD-ON Priority …
      eBay.com
      delivery truckFree shipping
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      (37)
      AVIDITI 16 X 12 X 6 Corrugated Card…
      ($1.97 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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      Medium Flat Rate Box - Random Sch…
      eBay.com
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      Upgrade From First Class Mail US T…
      Etsy
      delivery truckFree shipping
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      Priority Mail Upgrade, Small Flate Rat…
      $5.30
      Etsy
      SALE
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      Flat Rate Shipping Boxes Costs Com…
      dhgate.com
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      50 Qty The Scotty Stuffer-Largest Siz…
      eBay
      delivery truckFree shipping
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      BOX USA 20X16x4 Flat Corrugated B…
      ($2.11 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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      (32)
      BOX USA Shipping Boxes Flat 12"L X …
      ($2.75 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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      Aviditi 16X12x4 Corrugated Cardboa…
      $77.13
      AliExpress
      SALE
      delivery truckFree shipping
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      (3)
      16 X 16 X 5" Flat Corrugated Boxes, E…
      $67.96
      eBay
      SALE
      delivery truckFree shipping
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      BOXES FAST 20 X 16 X 4 Corrugate…
      ($2.60 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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      (36)
      TAPE LOGIC 20X16x6 Flat Corrugate…
      ($2.68 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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      Shipping Boxes Flat 16"L X 16"W X 4"…
      eBay
      delivery truckFree shipping
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      BOX USA 36X12x4 Flat Corrugated B…
      ($3.90 / 1 ct)
      Amazon.com
      delivery truckFree shipping
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    • Flat Rate Box Sizes | In Stock – Ships Today | Fast Delivery

    • The Official USPS® Website | USPS® Mail & Shipping Supplies

    • UPS® Official Website | UPS® Shipping Estimate