My classroom is a little lavish, built a piece at a time over many many years. Students are grouped in little tables each with a dedicated television that displays what’s going on. For a long time I taught from a podium with a Wacom Cintiq, a computer display with a pen. It’s super cool but bulky and required me to stay in one place as it’s hard wired to a computer. Over time, the cost to do what I do has plummeted. Televisions are incredibly cheap for what you can get (50”+ TVs are 1/3 of what they cost 10 years ago). The same goes for a device like a Cintiq.
I still like delivering material from a desktop computer, but an iPad and Apple Pencil make for an excellent input method. In the last year or so, AstroPad ($30) has turned into an incredible tool for interacting with a computer but using an iPad and its touch interface to do so. You need a desktop Mac of any recent vintage, and an iPad that supports an Apple Pencil to make this work. Though I use an iPad Pro, there are many flavors of iPad from the last couple years that support Pencils. You launch Astropad on the Mac and iPad, they communicate with each other and you have a wireless touch display for the computer. You can use a USB cable to connect the iPad as well if the wireless won’t work for whatever reason.
I now have a lot more freedom to seat students anywhere in the room and come to them when necessary.