The biggest roll of good duct tape that you can find in the budget.
useful for repairing stuff, and funny for suggesting they might have a screw loose, https://www.harborfreight.com/hardware/nuts-bolts/347-piece-nut-and-bolt-assortment-67621.html
itty bitty tweezers, https://smile.amazon.com/gp/product/B0B4G6Q416
Get a topo map of their area for free, print it out, frame it in a secondhand frame like you can find at any secondhand shop for cheap. Optionally include a whiteboard marker so they can draw on the glass over the map and wipe it off :)
a couple snack packs of freeze dried fruit, like https://smile.amazon.com/Green-Freeze-Dried-Fruit-Slices/dp/B07NQ1X27K, so they can see if they like it and order more if they do
a 10-pack of oxygen absorbers is $1 if you buy them in bulk -- https://smile.amazon.com/Oxygen-Absorbers-Storage-Canning-Freeze/dp/B0B4VTH79P
an everything-charger, https://smile.amazon.com/Braided-Charger-Compatible-Tablets-Samsung/dp/B08HGSVJS1/ref=sr_1_12, $4 apiece if you by the two-pack. Then when a friend from the other phone ecosystem runs out of battery, the recipient can save the day
Get some flashdrives in bulk for around $2 each, like https://smile.amazon.com/Enfain-Memory-Swivel-Indicator-Removable/dp/B00JES3MO0, and give all of wikipedia to a bunch of people