To "finance" something means to get or provide the money to pay for it. This word is only used for expensive things, like starting a company, building a factory, etc.
The word "finance" is interesting because it is used both with the person who's giving the money for something and for the person who's getting the money:
Our expansion is being financed by a private investment company.
I financed my education through a mixture of scholarships and student loans.