A million soccer fans are heading to Russia for the 2018 FIFA World Cup Russia Finals, where France will go up against Croatia on Sunday at 11 AM EST. And though the U.S. team isn't playing, more Americans are attending than residents of any other country.

"Data pulled in June at Booking.com showed that between the dates of June 14 to July 15, 2018, the United States ranked as the top nation, behind Russia, for bookings during The World Cup, followed by China, Germany, Argentina and Brazil," Booking.com's managing director of the Americas Todd Dunlap tells CNBC Make It.

The U.S. also leads World Cup flight booking growth to Russia, with bookings up 66 percent, according to Reuters.

So how much are Americans spending to attend the World Cup in Russia? About $6,200 per person for a three-night trip.

"Right now, if you booked nonstop flights from Washington D.C. to Moscow for the final, economy flights are about $2,350 per person," says Beth Jenkins, a travel adviser with McCabe World Travel, a Virtuoso agency. She has sold travel packages to Russia for nine years, and she has also coordinated travel to major events like the FIFA World Cup, 2016 Olympics and the Kentucky Derby.

"If you were able to get game tickets from the FIFA lottery, you could get face value of around $200-$250 per ticket, depending on the seat location. On the resale market, of course, tickets could be exponentially higher," Jenkins tells CNBC Make It. According to Goal.com, resale websites begin selling around $460 per ticket. Prime Category 1 sets can reach up to $105,000.

Booking.com found hotels starting at $44 a night at basic hotels ($132 total), or $236 for three nights at three-star hotels. Airbnbs are surprisingly cheap, with apartments as low as $27 per night, or $81 total for three nights.

U.S. travelers to Russia are booking packages with tour operators, and most operators require game tickets to be packaged with hotels and services together, says Jenkins. "This is often the best way to get hotel space, as tour operators contract rooms years in advance to have space for our clients, and the costs of services (touring, transportation) are at a premium."

Jenkins says the service costs are between $1,000 to $2,000 per person per day, thanks to World Cup surge pricing, which includes a local guide or escort, visits to attractions and experiences like the Kremlin, and all transportation, including airport pick ups. "Many companies have full day minimums (no half day services) so even if you just need a transfer, you have to book the driver for the whole day. This is not including hotels and ticket costs."

It is possible to book and go on your own but Jenkins recommends booking with a professional operator in Russia.

The good news, according to Jenkins, is that, once you get there, the exchange rate from U.S. Dollar to Russian Ruble is in your favor. A beer at the stadium costs about $5 U.S. — that's about 40 percent off from a typical $8 beer in a U.S. stadium.

Expect costs for dining out to be similar to the costs in a major U.S. city. "Moscow has a great restaurants from casual to fine dining, so you can dine out according to your budget," says Jenkins. She says expect more New York City prices for dinner, or an average of about $50.

Package service is minimum $1,000 a day, which is $3,000 total for a three-night trip. With a round-trip ticket ($2,350), game ticket ($460), lodging ($81 for three nights), and meals ($100 a day, or $300 total), the average total comes to $6,191.

Americans have spent almost the most money at the games, too. New, in-stadium data by Visa shows U.S. spent $3 million in purchases (Russians have spent $12 million). Mexico spent $1.5 million and China $1.1 million.

Russia expects a 15 percent tourism boost after World Cup, according to Reuters.

Don't miss:

Like this story? Subscribe to CNBC Make It on YouTube!