ISO Windows laptop

Looking for a laptop with Windows OS that I can use for programming and simulation work. I would love if it had a touchscreen and/or was a 2-in-1 (where the screen folds back and essentially makes the device a tablet), BUT not a deal-breaker if it doesn't. I can buy a new one at the school store for a little over $700 but I'm hoping to find a used one for under $400. Let me know!