Time capsule container

[LakeFlyPie]

I'm looking for a robust and relatively inexpensive time capsule container to use for a school time capsule project. The stainless steel ones I've seen so far seem to be £40+.
Any recommendations for more reasonably priced models please?

Don't mind me, I became excited thing you were talking about a time travel capsule. Obviously my day is very boring!

*thinking

Would a plastic tupaware tub work? You know the air tight containers, or would that be too small?

I used a glass jar that I taped up as a child. My parents found it recently, over 20 years later. The contents were a little damp but in tact.