To chip in

to contribute, as to a fund; to share in the risks or expenses of.

See also: Chip

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
He said: "When you take part in a World Cup there's always a lot of excitement and tension and everyone needs to chip in.
In very simplified terms, it works like this: Let's say you and your siblings want to chip in to buy a chainsaw for dad's birthday.