USCCB on “Cost of Catholic Weddings”:
The details are just as one would expect. For example:
“Traditionally, the couple makes a donation to the church in which they are married. Sometimes an amount—or a range—is suggested, but often it’s left to the discretion of the couple. If the bride or groom or both are registered parishioners, the suggested amount may be minimal, or none. The assumption is that they are already supporting the parish with their regular financial contributions.”
" In no case, however, should financial circumstances prevent a couple from approaching the Church for marriage."
“Some couples marry in a historic chapel or church. Keep in mind that wedding donations can be an important source of support for older buildings.”
If any person is presented with a “demand” for money to be married in their local suburban parish (and for other than real expenses, if any), that would be a serious matter.