Incidentally, about a year ago I got a 2012 Macbook Air base model for my little brother who is in 8th grade. He loves it.
I was able to get a broken one for free, cracked LCD and no battery. Found a battery with fewer than 20 cycles on ebay for ~$50, and a mint condition top case LCD assembly was ~$200. Approximately $250 all in, and a few hours of what I consider to be fun.
His school uses Google Drive for Education for a lot of the written homework and stuff, and it seems to work really well. Indeed, better than his older Chromebook in some instances.
I thought 128GB of storage would be insufficient, but it turns out he doesn't use that much. Documents and school projects don't take up that much space. He has under 20GB of music. Everything else data-intensive, like the instagrams and the snap chats, all reside on his phone anyway. Turns out 128GB works just fine.