The IPSI journals are self-supported non-profit journals, and the publication fee is needed in order to keep them alive.
Our unique feature is that we send each paper to 12 reviewers, and we make decisions based on at least 6 reviews, which is unique in the World. If your paper is accepted, you can put into your CV that the journal has the 75% rejection rate. Fortunately for you, the publication fee is to be paid only if your paper is accepted - we do not charge for the reviewing process, which is a very costly process. The publication fee is calculated so that the journals are at positive side of zero, not generating any profit (that is why the publication fee is relatively small).
Sincerely Yours,
Prof. V. Milutinovic, Editor-in-Chief,
Fellow of the IEEE