Because the 3DS eShop has closed and physical media is becoming obsolete, dev kit prices have skyrocketed. As of this year, here are the rough benchmarks:

This unit physically resembles a retail 3DS but with a distinctive screw-on backplate and usually a or label. These are technically "debug" units. They play retail cartridges but also accept development cartridges (large, bulky flash cards). They are highly sought after because they often fit in standard chargers and cases.

Unlike standard retail Nintendo 3DS units, dev kits include specialized hardware and software:

The earliest prototypes, sometimes called "Panther" (the 3DS codename). These are incredibly rare and look like a translucent plastic shell with wires visible. If you find one of these for sale, expect to pay a museum-level price.

: Alongside the hardware, the kit came with a suite of software tools for coding, debugging, and testing. These tools were indispensable for identifying and fixing issues early in the development process.