Walk into any packaging warehouse and you'll see poly bags in a dozen variations. Three types account for most orders: flat bags (open top), zip lock bags (resealable), and self-adhesive bags (peel-and-seal).
Each one solves a different problem. Here's how to choose.
📄 Flat Bag
Open top, heat-seal or tie
Lowest cost per bag
🔒 Zip Lock Bag
Double-track zipper, reusable
Best for repeated access
📬 Self-Adhesive Bag
Peel-and-seal, no equipment
Clean, professional look
Flat Bag -The Workhorse
A flat bag is exactly what it sounds like: a simple bag with an open top and a sealed bottom (or side). No closure mechanism -you fill it and seal it with a heat sealer, tape, or tie.
- Best for: Products that are sealed once and opened by the end customer. Garments, bread, hardware parts, dry goods.
- Advantages: Lowest cost per bag, fastest production, simplest design.
- Considerations: Requires a sealing step (heat sealer or tape). Not reusable.
- Price range: $3.45-4.50/kg (virgin LDPE).
Zip Lock Bag -The Reusable Solution
A zip lock bag has an integrated double-track zipper at the opening. Press to seal, pull to open. Can be reused hundreds of times.
- Best for: Products that need repeated access. Electronics components, small parts, food portions, travel kits.
- Advantages: Reusable, no sealing equipment needed, liquid-tight option available.
- Considerations: Higher cost than flat bags. Zipper adds thickness at the seal area.
- Price range: $5.24-6.85/kg.
Self-Adhesive Bag -The No-Equipment Option
Self-adhesive bags (also called peel-and-seal bags) have a strip of adhesive covered by release paper. Peel the paper, fold the flap, press -sealed. No heat, no zipper.
Two sub-types exist: peel-and-seal (adhesive strip on flap) and fold-over flap (tuck-in closure without adhesive).
- Best for: Documents, small accessories, jewelry, samples, lightweight e-commerce items.
- Advantages: Manual seal only -no equipment needed. Clean, professional look.
- Considerations: Adhesive performance varies with temperature. Not suitable for heavy items.
- Price range: $4.50-5.90/kg.
Quick Decision Flowchart
Need the bag to be resealable?
→YES: Zip lock bag (repeated access) or self-adhesive (single reseal)
→NO: Flat bag (lowest cost)
Have a heat sealer on hand?
→YES: Flat bag -fastest and cheapest
→NO: Self-adhesive (peel-and-seal) or zip lock
Selling to end customers directly?
→Zip lock or self-adhesive: better perceived value
→Flat bag if it's inside another package (e.g., garment box)
FOB Price Comparison Table
| Bag Type | Price/kg (FOB) | Relative Cost | Best Use Case |
|---|---|---|---|
| Flat Bag | $3.45-4.50 | $$ (Lowest) | Bulk packaging, garments |
| Self-Adhesive | $4.50-5.90 | $$$ | Documents, retail items |
| Zip Lock | $5.24-6.85 | $$$$ | Reusable, food, electronics |
Need exact pricing for your specific size and quantity? Use our Instant Price Estimator or contact us for a custom quote.
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