An IPOstands for Initial Public Offering. It is the point in which a company sells common stock to the public. Money raised from an IPO goes to the company directly as opposed to the trade of stock that is already being bought and sold. The purpose of selling stock to the public is to raise capital, which could be used to for mergers and/or acquisition.
Since an IPO is an equity transaction there are no financing considerations for the IPO itself. Other financing considerations for a merger or acquisition would be financing in the form of bank loans or bond issues, which would have to be repaid with interest. Additional investments from the owners, in the case of non-public companies, would also be a consideration, but this would be considered an equity transaction.