The Raspberry Pi 400 is a computer stuffed inside a keyboard, featuring a quad-core ARM Cortex-A72 processor, 4GB of RAM, WiFi, Bluetooth, and a starting price of $70 for the computer alone or $100 for a computer + mouse, power supply, and microSD card with Raspberry Pi’s Linux-based operating system pre-installed.
One thing that’s not included? A display. You’ll need to supply your own.
But if you don’t happen to have a spare monitor lying around and/or you’re looking for something a little more portable, Waveshare’s got you covered — the company is selling a line of Raspberry Pi 400 kits that come bundled with touchscreen displays.

There are two options available at the moment:
Both screens have built-in kickstands, allowing you to stand them up while paired with a Raspberry Pi 400 or other devices. And both have HDMI inputs for video and USB inputs for touch support.
The 13.3 inch version also has a built-in speaker, supports 10-point multitouch input, has a resolution of 1920 x 1080 pixels, and requires its own power supply (in addition to the power supply that keeps the Raspberry Pi itself running).
The smaller model has a 7 inch, 1024 x 600 pixel touchscreen display with support for 5-point multitouch input, no speaker, and no need for a separate power supply – it can draw power from the Raspberry Pi via USB.

While neither kit will completely transform a Raspberry Pi 400 into a laptop (you’d need a battery pack for that), they could make the little computer-in-a-keyboard a little more useful.
And if you already have a Raspberry Pi 400 or a similarly small computer and just want to pick up the displays, WaveShare sells them independently as well. The 7 inch model is available for $72, while the 13.3 inch version sells for $160.
via CNX Software
The main failure is at those prices you might as well buy a laptop. Unless you desperately need a gpio and sdcard boot.
A regular raspberry pi connected to a nexdock ($305) seems competitively priced with the 13″ set plus a battery pack and 3 ring binder.
Better value
https://www.walmart.com/ip/Lenovo-81JW0001US-Chromebook-S330-14-HD-Display-Mediatek-MT8173C-CPU-4GB-RAM-32GB-eMMC-SSD-Chrome-OS-Black/206750547
$199
If people cared about cost/performance…the raspberry pi(and all SBC’s) wouldn’t exist. They’re worthless…
I wouldn’t have bought it up if you hadn’t mentioned GPIO.