To answer your question about who pays, today most weddings are paid for by the couple and both sets of parents, though not necessarily equally. If parents want to help, they volunteer and they decide whether they want to give the couple a sum of money or pay for certain items, such as the photography or the food. If parents don't volunteer, then it is the responsibility of the couple to pay for their wedding.

More people have gotten themselves into more trouble -- often poisoning important relationships at the worst possible time -- by informing their parents/in-laws/attendants that they "have to" pay for, plan, or do something and shoving a book under their noses as if that made it a law. Don't you fall into that trap.

A wedding reception is, after all, just a party. So, like any other party, the hosts pay. That may be the bridal couple, one or both sets of parents, someone else, or some combination. Often, of course, someone else will offer to the hosts to contribute something -- a dollar amount, the liquor costs, or whatever. How that all plays out depends upon your circumstances. Say the bride and groom are planning and hosting the wedding. Their families may offer to contribute, especially if they are requesting to invite more guests than the couple had budgeted. Or say the bride's parents are hosting. They may tell the couple something like, "We are happy to spend $X on this wedding. Now you decide what you would like (e.g., more people and less expensive arrangements, or fewer people at their dream reception)." The groom's parents (or the bridal couple) may offer to contribute, or not, or they may decide to host some other event.

Do you see why there couldn't possibly be a "rule" about Who Pays that would be one-size-fits-all for the financially independent older couple, the young bride and groom from wealthy families, for the bride from a huge, local family and the groom from a tiny, distant one -- etc.?

The same is true for what I think you mean by "a lot of the traditions." Books can give you interesting and useful information, of course. But no book can tell you what YOUR families' and communities' traditions are. If they are different from what is in the book, you aren't going to get anywhere by insisting "But it's in the book!" if someone is unhappy that you are flouting their tradition.