plastic plant pot

One mans rubbish is another man's treasure! People often throw them.
If you visit your local recycling centre ask them. They usually give them to you for free or you can collect them yourself.

They are readily available in every garden centre in the country.
I have a huge range of all sorts of sizes and I'm never going to use them. You are welcome to them though I live about 40 minutes drive from Brussels.
If you are interested, post a contact email and I'll let you know sizes, shapes and quantities.