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Prep Center vs. Prepping FBA Inventory Yourself: The Real Cost
Short answer: Prepping yourself looks free, but it costs your time (often 4 minutes or more per unit to receive, inspect, label, bag and pack), your supplies and, if you live in a sales-tax state, the tax on everything you buy. Once you're past a few hundred units a month, a prep center in a no-sales-tax state can cost less in cash than doing it yourself, especially with higher-priced items, and gives you back dozens of hours a month.
What DIY prep really costs
- Time. Opening boxes, checking every item, covering barcodes, printing and applying FNSKU labels, bagging, building boxes, weighing and labeling them. Without a dedicated setup, 4 minutes per unit is a realistic average for most people, more for bundles and fragile items. It adds up fast.
- Supplies. Labels, label printer, poly bags with warnings, bubble wrap, boxes, tape, a scale. These cost money every month.
- Sales tax. When retail purchases ship to your home in a sales-tax state, you pay that state's tax on every order: 7.5% on average across the US, over 9% in states like California, Washington and Tennessee.
- Space and mistakes. Inventory takes over a room or garage, and a labeling or prep mistake can mean refused units or extra Amazon fees.
Side-by-side example
A seller buying 800 units a month at an average cost of $30, in a state with the national average sales tax (7.53%). Supplies are assumed at $0.10 per unit; yours may differ.
| Per month | Do it yourself | PrepWorx |
|---|---|---|
| Sales tax on $24,000 of purchases | $1,807 | $0 |
| Prep supplies | $80 | Included |
| Prep fee (800 × $1.25) | $0 | $1,000 |
| Receiving (about 10 boxes × $1) | $0 | $10 |
| Cash cost | $1,887 | $1,010 |
| Your time (4 min/unit) | About 53 hours | About 0 hours |
Before counting your time at all, the prep center is about $877 a month cheaper, over $10,500 a year, because the sales tax you stop paying is bigger than the prep fee. On top of that you get back roughly 53 hours a month, more than a full work week, to spend sourcing instead of labeling. In a higher-tax state like California (9.03%), the tax alone is $2,167 a month, so the gap grows to about $1,237 a month.
Want to run your own numbers? Try the savings calculator on our home page.
When doing it yourself makes sense
- Very low volume, such as a few dozen units a month, where a monthly minimum spend outweighs the savings.
- You live in a no-sales-tax state (Oregon, Delaware, Montana or New Hampshire), so there's no tax to save.
- You want to personally inspect every high-value or collectible item.
- You're still learning. Prepping your first few shipments yourself teaches you Amazon's rules.
When a prep center wins
- You're past a few hundred units a month and prep is eating your evenings and weekends.
- You live in a high-sales-tax state and buy at retail, as with online arbitrage.
- You're running out of room. Boxes are taking over your garage, spare room or apartment, and there's nowhere to put the next order.
- You want to scale without renting space or hiring help.
- Q4 is coming. Holiday volume is when DIY prep breaks down.
- You want to travel or step away without your business stopping.
A middle path
Many sellers start by sending only their bulk or online purchases to a prep center and keep prepping local finds themselves. Once they see the time they get back, they move more over.
Example uses PrepWorx's published rate for 500–1,000 standard units a month ($1.25) and $1 per box received, as of October 2026. Time and supply figures are estimates. Your results will vary.
Common questions
How long does it take to prep one unit for FBA?
For most people, around 4 minutes per unit or more, including receiving, inspecting, labeling, bagging and packing boxes. Bundles, fragile items and anything needing bubble wrap take longer. A trained team with a dedicated station is much faster.
At what volume is a prep center worth it?
For sellers in sales-tax states buying at retail, often at a few hundred units a month, because the tax saved covers much of the prep fee. Below that, it depends on how much your time is worth.
Is there a minimum to use PrepWorx?
There's no volume minimum. There is a $100/month minimum spend, and the first 30 days have no monthly minimum.
Get your weekends back
Send your inventory to PrepWorx in Oregon. No sales tax, 24-hour average turnaround, and we handle every label and bag.
