Do you have to pay for seminary? I saw that FSSP was quite expensive but was wondering if this is a different situation compared to more traditional seminary and schools of formation.

I suppose it would depend mostly on how wealthy the seminary and the diocese that sent you there were, I imagine that if the diocese can afford to cover the entire cost, they probably do, or at least at much of the cost as they can afford.

The FSSP are religious instead of diocesan and get their funding differently. The diocese takes up a collection once a year for the seminary and has a much larger budget, the order just has to support themselves through donations.

How seminary is funded varies from diocese to diocese, and probably from order to order.

Back when I had money, I gave a lot of it to FSSP to fund their seminaries.

I think the OP was asking if a young man who decided to be a priest would have to pay to attend the seminary. I assume the answer to this is no, at least I hope so.

That was the question and it was answered "it depends on the diocese how the seminary education is paid for", that's it, that's the answer.

It's not always no.

In the diocese I live in we have a Burse Club that parishioners can voluntarily join, and donate $1.00 a month, collected by volunteers at the doors of the church before and after Sunday Mass once a month. Some do donate more, but even at $1.00 a month from many parishioners in our entire diocese, much is collected. Also, the various Ladies Societies and other groups donate from their fund raisers as well.