i agree i think the unique sound came from landing on already deposited coins rather then the container/buckets material.
Partially correct. The sound of a coin going into a coinbox that is nearly empty is much different than when there are coins in it. You can almost tell how full the coin box is based on sound.
Regardless, if someone wanted a more authentic sound with a tupperware container, they just need to make sure they leave a good bit of spare change in the "coinbox", as gamester pointed out.
EDIT: Another cheap idea that may work, get an old metal hubcap* and place that in the bottom of the container (or duct tape card paper around the sides to prevent stray coins). This should help make the hollow clinking sound that a nearly empty coinbox makes, and then transition to the sound of a more full coinbox as it fills up. ( * Car hubcap, sheetmetal ashtray, baking pan, etc)