Allocating the costs of open access
Open access does not necessarily incur extra costs: if the terms and conditions of the publisher are in line with those of the funding agency, you can allow open access free of charge (Green Open Access). If you have to choose publishing in journals that charge for open access (Gold Open Access), it will mean additional costs, article processing charges (APC), for your research project.
Universities often have agreements with some publishers, whereby the university may pay for a portion of the costs or get a discount on the charges; for more detailed information, you should consult the library of your university. The research funding agencies requiring or encouraging open access (e.g. the Academy of Finland, the EU) usually consider the article processing charges as eligible project costs.