pitch in
phrasal verbpitch in (with somebody/something) 
- (informal) to join in and help with an activity, by doing some of the work or by giving money, advice, etc.
- Everyone pitched in with the work.
 - Local companies pitched in with building materials and labour.
 
 
pitch something  in 
- to give a particular amount of money in order to help with something
- We all pitched in $10 to buy her a gift.