plastic milk jugs ...mason jars...paper mashay a baloon
Ooh there are so many ways of making planters - for outdoors we have made planters from the rotting side of old sheds but you could easily use pallets. If you check out Hometalk there are lots of ideas from buckets, to concrete, an old shower caddy as a wall planter, old drawers.
Indoors I have used old ferrro roche boxes, cut in half wine bottles, tea seat, cake tins, tin cans https://vickymyerscreations.co.uk/?s=planter
Naomi: Here are some terrific ideas!
You can use any container for a planter as long as it will drain. Small planters can be plastic containers you spray for decoration, to buckets, to coal buckets, to wheel barrows, to wooden rectangular planters to laying logs down around a tree and filled with planting soil. The size, shape and location can be just anywhere you want it as long as you have adequate sunlight in that part of the yard for what you want to grow.