i made a smokeless alcohol stove today while at lunch for under 10 bucks. all you need is a gallon paint can, a quart paint can (both ideally unused), a bottle of isopropyl alcohol (go for the 91%), a roll of toilet paper, and a way to punch holes.
yank the core out of the TP, and possibly peel off a few layers, and crush it down as tight as possible and cram it in the quart can. add the alcohol until it’s fully soaked. now you’ve got a fuel source which can be resealed for later use, and apparently will burn for 6-8 hours.
next, punch a few draft holes in the base of the gallon can (which is for wind protection and easy fire quelling, because this thing makes A LOT of heat). set the quart can inside, and light it with a match or a grill lighter or a firesteel from a decent distance, as it catches instantly. enjoy your new campfire.
when you want to kill it, just set the gallon lid back on the can and it will go out in a few seconds. i threw my kelly kettle grills on there, and the kelly kettle itself, and had tube steaks and boiling water in no time.