Every Windows or Office key you can buy falls into one of three licensing channels: retail, OEM, or volume. They all activate the exact same software — the difference is entirely in how the license is sold and what terms come attached, which is also the biggest reason prices vary so much between sellers.
Retail Licenses
A retail license is the one Microsoft sells directly through its own store at full price. It's transferable — meaning you can move it to a new PC if you upgrade or replace hardware — and it's the most flexible option, which is exactly why it costs the most.
OEM Licenses
OEM (Original Equipment Manufacturer) licenses are meant to be sold alongside new hardware by PC builders and system integrators — legally, an OEM key is tied to the first motherboard it's activated on and isn't meant to transfer to a different PC afterward.
In practice, this is the most common type of genuine key sold at a discount: legitimate OEM keys purchased in bulk by authorized distributors and resold individually to end users building or upgrading a single PC. The software itself is fully genuine and activates normally — the trade-off is simply that it's meant to stay with one machine rather than following you across every future PC.
Volume License (VL) Keys
Volume licenses are sold in bulk to organizations — a business might buy 200 Windows Pro licenses under one agreement to deploy across their office. These keys often use Key Management Service (KMS) activation rather than individual online activation, since they're designed for IT departments managing many machines at once, not a single consumer PC.
Why This Explains the Price Difference
Retail costs the most because it's the most flexible. OEM costs less because it's scoped to a single machine — and that's exactly the licensing type most legitimately discounted keys you'll find online actually are, not because they're fake, but because the terms are narrower.
For a full breakdown of why this makes low-priced keys legitimate rather than suspicious, see our guide on whether cheap software keys are legit.
