This is a little device I mading that uses the way sand falls to it's advantage. Please comment if you liked it and maybe give suggestions. Also, if you liked it, please give me a diamond, it will make my day! Basically how it works is that you hit a button and it activates a dispenser with the given food in it. That will go into a water flow, but be stopped by an extended piston. Then you go over to the place where you pay, and place down 5 blocks of sand or gravel. They will fall and stack on top of each other, and once the 5th one is placed has a powered redstone repeater going to it. On the other side of the repeater, there is redstone leading to the piston that held back the item from before. The redstone also goes to a very non-compact redstone lengthener (I don't know if that's what you call them, thats just what I call them) that opens up a piston under the fallen sand, and the sand falls into the void. The redstone lengthener is 8 ticks, just long enough to get the sand out of there. Then you walk out and eat your food happily.

Some people may ask why the falling sand does not trigger the redstone repeater setup, and that is because when sand is falling it becomes an entity and entities do not trigger redstone alone.

Hope you like it, I don't mind if you want to bother to compact it and use it in something! It could use lots of compacting. If you want more stuff like this from me, you can request something in the comments or just subscribe to me! Thanks!