  The Plan S initiative is expected to radically change the market of scholarly
periodicals, resulting in the abandoning of the subscription model in favour of
the open access model. This transition poses new challenges, as well as sets
new tasks for researchers, managers, librarians and scientific publishers,
particularly in countries with transforming economies. In this study, we set
out to estimate approximate costs and future prospects associated with the
transition of Belarus and Ukraine towards open access to scientific information
on the example of publications by researchers from these two countries in
Elsevier journals. To this end, we accessed the Scopus database and selected
all papers affiliated with Belarus and Ukraine published by Elsevier journals
in 2018. Subsequently, we established which of these articles indicated a
corresponding author from Ukraine or Belarus, as well as collected journal
titles, correspondence addresses, access types and the APC fee for each
article. In addition, funding sources were established for each open access
article. This allowed us to determine the total amount of money that Ukraine
and Belarus would have needed to pay so that all the articles of their
researchers, which were published in Elsevier journals in 2018, were available
in an open-access form. The obtained results show that Belarus and Ukraine are
currently under-investing in the support of scientific publications and
subscription to scientific resources, which is necessary for making a
transition to the model of open access to scientific literature. The proposed
method for calculating the expenses of publishing papers written by researchers
from a given country in open access can be used in the preparation of
transformative agreements with developing countries.
