As more of my friends start to get married, it's hard to know what to budget [1] as a guest. A hundred bucks? Three hundred? More?

Financial services business American Express [2] recently compiled data to help us better understand how much guests cough up for the big day (check it out here [3]). And let's just say, it's not too pretty.

On average, Americans are spending $703 per wedding this year.

In 2015, guests spent $673, which means the cost is up five percent. Even worse? Guests who are part of a wedding party can expect to pay $743 (again, up from last year's cost, which was $701).

So what's causing a wedding guest to fork over SO much cash? The items contributing to these total prices include airfare, pet/childcare costs, and attire [4] for the event. Those dance-floor Snapchats require the perfect outfit, after all.

Perhaps the most surprising is the demographic paying the most. According to the research, high spending among millennials is an up-and-coming wedding trend. They're dishing out more than the average population by a whopping 27 percent ($893 on average).

As for the wedding gift itself, Americans can expect to pay an average of $127 on a relative's nuptials vs. $99 for friends who are tying the knot.

As for the bride and groom, the data show that over half of Americans (53 percent, to be exact) are throwing self-funded weddings. This explains why most married couples (55 percent) have incorporated some type of DIY [5] project into their affairs, such as devising their own wedding albums, creating crafty centerpieces, and assembling guest favors [6].

At least guests can count on those favors . . . right?