that's called crowd funding

wiki:

Crowd funding or crowdfunding (alternately crowd financing, equity crowdfunding, or hyper funding) describes the collective cooperation, attention and trust by people who network and pool their money and other resources together, usually via the internet, to support efforts initiated by other people or organizations.[citation needed] Crowd funding occurs for any variety of purposes,[1] from disaster relief to citizen journalism to artists seeking support from fans, to political campaigns, to funding a startup company, movie [2] or small business[3] or creating free software.