How to Source Custom Flexible Packaging: A 7-Step Checklist for Busy Procurement Teams

Who This Checklist Is For

If you're a procurement person, office admin, or operations coordinator tasked with finding packaging suppliers for cosmetics, pet food, or custom food packaging bags—and you don't have a dedicated sourcing team—this is for you.

I manage vendor relationships for a 120-person company. About $85,000 annually across 11 vendors. Packaging is one of my categories. I've placed roughly 200 packaging orders in the last four years, and I've made enough mistakes to fill a small notebook.

This checklist has 7 steps. Each one includes a checkpoint so you know when you're done. I'll also flag the mistakes I see most often at the end.

Step 1: Define Your Specs Before You Talk to Anyone

Most buyers start by requesting quotes. That's backwards. You'll get 10 different quotes for 10 different things if you haven't locked your specs first.

Here's what you need to nail down:

• Dimensions (flat width, height, gusset depth if applicable)
• Material type—PE, PET, kraft, compostable films, etc.
• Closure style—zipper, heat seal, tin tie, etc.
• Print requirements—how many colors, front/back, matte or gloss finish
• Volume—annual estimate and first-order quantity

Checkpoint: You can describe your packaging in one paragraph without saying "something like."

I learned this the hard way. In 2021, I sent a vague request to six vendors for "custom cosmetic bags, maybe 10,000 units." I got quotes ranging from $0.18 to $0.72 per unit. They were quoting completely different products. I wasted two weeks and looked like I didn't know what I was doing.

Step 2: Vet Suppliers for Certifications—Not Just Price

If your packaging touches food, cosmetics, or pet products, certifications aren't optional. They're the floor.

Ask for:

• FDA compliance for food-contact materials (21 CFR 177)
• ISO 9001 for quality management
• BRCGS or SQF if you're in food or pet food packaging
• FSC certification if sustainability claims matter to your brand

Don't accept "we follow all regulations" as an answer. Ask for certificate numbers and expiration dates.

Checkpoint: You have PDF copies of current certificates from at least three suppliers.

To be fair, smaller suppliers sometimes have solid operations without every certification. But if they can't produce documentation, that's a red flag for me.

Step 3: Request Physical Samples—Not Digital Mockups

A digital mockup tells you nothing about how the bag feels, how the print actually looks, or whether the zipper works smoothly.

Ask each supplier for:

• 2-3 physical samples of similar products they've produced
• Material swatches for the film you're considering
• A printed sample with your artwork if possible (some charge for this, some don't)

Checkpoint: You've held the packaging in your hands and tested the closure at least 10 times.

I once approved a supplier based on digital proofs. The actual bags arrived with colors that were noticeably off—the brand blue looked purple. The supplier said "screen calibration differences." We ate $3,200 in reprints because I skipped this step.

Step 4: Verify Sustainability Claims Before You Repeat Them

"Compostable," "recyclable," "eco-friendly"—these words are everywhere. And they're regulated.

Per FTC Green Guides (16 CFR Part 260), environmental claims like "recyclable" must be substantiated. A product claimed as "recyclable" should be recyclable in areas where at least 60% of consumers have access. Source: ftc.gov/green-guides

Ask your supplier:

• What specific certification backs the compostable claim? (BPI, TÜV OK Compost, etc.)
• Is the entire package compostable, or just the film? (Zippers and valves often aren't.)
• Can you provide documentation I can share with my marketing team?

Checkpoint: You have written confirmation of what the sustainability claim actually means and what certification supports it.

The way I see it, if a supplier gets defensive when you ask for documentation, that tells you something.

Step 5: Get Total Landed Cost—Not Just Unit Price

The per-unit price is a starting point, not the final number. Most buyers focus on unit cost and completely miss setup fees, plate charges, freight, and minimum order surcharges that can add 30-50% to the total.

Ask for a breakdown that includes:

• Plate/setup fees (one-time or per-order?)
• Minimum order quantity and what happens if you order less
• Freight cost to your location
• Lead time and rush order fees
• Payment terms and any finance charges

Checkpoint: You can compare three suppliers on total landed cost for the same order volume.

I had a vendor quote me $0.22 per unit that looked like the cheapest option. After adding $450 in plate fees, $380 in freight, and a 3% credit card surcharge, it was actually the most expensive quote. Bottom line: always ask for the all-in number.

Step 6: Confirm Shipping and Mailing Compatibility

If your packaging will be mailed or shipped individually, you need to check size and weight against carrier specs.

USPS defines standard envelope dimensions as: - Letter: 3.5" × 5" minimum to 6.125" × 11.5" maximum - Large envelope (flat): 6.125" × 11.5" to 12" × 15" - Thickness: 0.25" max for letters, 0.75" max for large envelopes Source: USPS Business Mail 101 (pe.usps.com)

If your custom food packaging bags or cosmetic packaging will be mailed, confirm that the filled package stays within your target mail class. Otherwise, you're looking at package rates instead of envelope rates—which can double your postage.

Checkpoint: You've weighed a filled sample and confirmed it fits your shipping budget.

Step 7: Run a Small Test Order Before Committing

This is the step most people skip. Don't.

Order 500-1,000 units first. Yes, the per-unit cost is higher. Yes, it adds a few weeks. But it's cheaper than discovering a defect after 20,000 units.

Use the test order to check:

• Print quality and color accuracy
• Seal strength (do the bags hold up?)
• Zipper function after filling
• Actual lead time vs. quoted lead time
• Invoice accuracy and packaging of the shipment itself

Checkpoint: You've filled and handled 50+ units from the test order without issues.

After 5 years of managing procurement, I've come to believe that the "best" packaging supplier is the one who communicates clearly, documents everything, and ships on time—not the one with the lowest quote.

Common Mistakes to Avoid

1. Skipping the test order to save time. It never saves time. It just delays the problem.

2. Assuming a low quote means efficiency. What they don't see is which costs are being hidden or deferred. Ask for the full breakdown.

3. Accepting verbal sustainability claims. Get it in writing. If your marketing team repeats a claim that isn't substantiated, that's an FTC issue.

4. Forgetting about storage. Where will 20,000 bags live? If you don't have warehouse space, ask about staggered deliveries or fulfillment services.

5. Not verifying invoicing capability. This one cost me personally. In 2021, I found a great price from a new vendor—about 30% cheaper than our regular supplier. I ordered 15,000 units. They couldn't provide a proper invoice (handwritten receipt only). Finance rejected the expense report. I ate $2,400 out of the department budget. Now I verify invoicing capability before placing any order.

None of these steps are complicated. But doing them in order—and actually completing each checkpoint—will save you from the mistakes I've already made.