Kitting and Bundles, Explained: When It Saves Money (and When It Doesn't)

If you sell bundles — a starter kit, a gift set, a subscription box — your 3PL has probably mentioned kitting. The pitch is that pre-assembling bundles ahead of time speeds up shipping. That's true. What's also true is that kitting costs money, and whether it pays off depends on math most founders never run.

What kitting actually is

Kitting is taking multiple SKUs and combining them into a single new SKU before any orders come in. Your 3PL receives bulk inventory of the components, assembles them into bundles, and stores the finished bundle ready to ship as one unit.

The alternative is on-demand assembly: when an order for a bundle comes in, the picker grabs each component, assembles, and ships. Same end result for the customer. Different cost structure for you.

How 3PLs charge for kitting

• A per-unit kitting fee — typically $1–3 depending on complexity.
• A setup or project fee for the first run.
• Sometimes additional packaging materials (kit boxes, inserts).
• Storage on the finished kit, usually billed separately from components.

When kitting saves money

Pre-kitted bundles win when:

1. The bundle ships frequently and consistently — predictable demand.
2. On-demand pick fees for each component would exceed the kitting fee.
3. The components are awkward to pick together (different storage zones).
4. Speed matters and you can't afford the extra pick time during peak.

Example: a 4-component starter kit. On-demand picking might cost $4 in pick-and-pack fees per order. Pre-kitting might cost $2 per kit upfront. If the bundle sells reliably, kitting wins.

When kitting is a trap

Pre-kitting hurts you when:

• The bundle is a slow mover — you're paying to assemble units that sit.
• You change the bundle composition often (seasonal swaps, sample updates).
• Components are also sold individually — you've now duplicated inventory.
• Storage on the finished kit is higher than storage on the components.

The hybrid approach

You don't have to pick one. A common setup: pre-kit a few weeks of expected demand based on your forecast, fall back to on-demand assembly if you blow through it. This caps your upfront kitting spend while keeping the benefit on the bulk of orders.

What to ask your 3PL

1. What's your per-unit kitting fee for a 2-, 3-, and 5-component kit?
2. Is there a setup fee?
3. Do I get billed storage separately on the finished kit and the components?
4. What's the lead time to kit a new run if I run out?
5. Can I unkit a bundle if it doesn't sell, or is the labor sunk?

Last question is the one most founders forget. If a bundle flops, you want the option to break it back into components and sell them individually without paying labor twice.