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Last month, not knowing how much my packages weighed cost me over $50 in shipping mistakes while selling some things I no longer need.

To fix that, I purchased the Saga Mercury 66 lb Digital Postal Scale — and after about a dozen shipments, it has practically paid for itself.

Quick Verdict

The Saga Mercury is one of the cheapest accurate postal scales available. It’s precise to 0.1 oz, compact, and perfect for eBay sellers or small business shipping.

If I were buying again, I’d choose the 86 lb version for the backlit display.

Pros
  • Accurate to 0.1 oz
  • Hold function for large boxes
  • Very affordable
  • Multiple power options (USB, AC, batteries)
  • Pays for itself quickly
Cons
  • No backlit display on 45 & 66 lb models
  • No computer connectivity (despite “USB” in title)
  • Plastic construction

Why Every eBay Seller Needs a Postal Scale

Unless you're using Priority Flat Rate boxes, weight is the biggest factor in shipping cost.

I made the mistake of copying shipping prices from similar listings. For heavier items, I underestimated costs and ended up eating the difference. In one case, shipping cost me 40% of the sale price.

Once I started weighing packages accurately and printing labels at home, I saved:

  • USPS online discounts
  • UPS discounts when linked through PayPal
  • Avoided 30% third-party shipping store surcharges

That alone justified buying the scale.

Available Models

  • 45 lb version
  • 66 lb version (what I purchased)
  • 86 lb version (only version with backlit display)

If I knew then what I know now, I would have spent a few dollars more for the 86 lb model.

Accuracy

The scale claims accuracy to 0.1 oz — and that matches my experience.

I’ve compared readings directly with:

  • USPS counter scales
  • UPS drop-off locations

Readings are consistently within ±0.1 oz.

For best accuracy:

  1. Place on flat, level surface
  2. Turn on
  3. Press Tare
  4. Place package

It also measures in pounds, ounces, and kilograms.

Hold Function (Very Useful)

Because the scale is compact, large boxes can block the display.

Press the Hold button before placing the package. After 5 seconds, remove the package and the weight remains displayed.

It’s slower than high-end USB scales but perfectly functional.

Important Note About “USB”

Despite having “USB” in the title, the scale does NOT connect to your computer.

The USB cable only powers the scale. There is no data connection.

Lift-Up Lid Feature

The top flips up, allowing large envelopes to stand vertically so you can see the display.

Under the lid is a small USPS rate chart. I personally check rates online instead.

Other Uses

The scale can also be used for:

  • Kitchen measurements
  • Weighing small pets
  • General household weighing

Just note the sticker underneath: “Not Legal For Trade.” This means you cannot use it to sell items by weight commercially.

Specifications

Max Weight 66 lb (model reviewed)
Resolution 0.1 oz (5 grams)
Power Options AA batteries, AC adapter, USB power
Display Non-backlit (66 lb version)

Final Thoughts

This is one of the cheapest accurate postal scales available.

It’s plastic, simple, and not fancy — but it works.

For anyone shipping multiple packages per week on eBay, Etsy, or a small business website, it will likely pay for itself quickly.

If I were buying again, I would get the 86 lb version for the backlit display.

Overall, I’m very glad I purchased it.

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