I think a refurbished/ used laptop would be a better bang for the buck. It will be heavier than a mini boxe or a chromebook but it comes a screen (any screen is better than no screen), a battery, a keyboard, a touch pad and DVD.
I bought a used Latitude e6420 for $200 around10 months ago, replaced DVD with an extra hard drive, added extra USB ports to the express card slot and installed Linux on it. Latitudes are heavy and don’t have a great screen but they are rock solid. I usually do culling sorting tagging etc. when on the laptop screen and plug it in to an external monitor when post processing pictures in darktable.