A sizable down payment can help keep your monthly mortgage bills more manageable, but first-time homebuyers often have trouble coming up with this deposit. A new report by the real estate site Zillow suggests that lavish pre-wedding celebrations might be contributing to this problem.

Zillow's analysis is based on the idea that destination bachelor and bachelorette parties have become more popular, particularly among young potential buyers. Instead of a local get-together, the bride and groom may be more inclined to take a weekend trip to wine country, Las Vegas, or some other interesting place. The wedding planning site The Knot says guests at these bachelor or bachelorette parties are expected to not only cover their own expenses for travel, accommodations, and activities, but chip in to pay for the bride or groom as well.

The Knot pegs the average cost of a destination bachelor party as $1,532, while the typical destination bachelorette party comes to $1,106. For their study, Zillow looked at the cost of a person attending nine average priced parties in a three-year period. This would amount to $13,788 for men attending bachelor parties and $9,954 for women attending bachelorette parties.

Zillow puts the median cost of a home in the United States at $200,400. A home at this price would require $40,080 for a 20 percent down payment, which is usually recommended since it allows borrowers to forego private mortgage insurance and secure a favorable mortgage rate.

The study suggests that a man attending nine destination bachelor parties would spend more than one-third of the cash needed for a down payment—34.4 percent—on the trips. A woman attending nine destination bachelorette parties at the average cost would use up 24.8 percent of the savings needed for a typical 20 percent down payment.

The impact of these trips varies depending on the market. In San Jose, Calif., where the median home price is $1.01 million and a 20 percent down payment amounts to $202,740 – more than the national median home price. A typical destination bachelor party would amount to only 6.8 percent of this down payment, while the average bachelorette party would only require 4.9 percent of these savings.

In Cleveland, attending nine average priced destination bachelor parties would use up more than half of the savings necessary for a down payment on a typical home. The median home in this market has a price of $134,600, so a down payment would cost $26,920. The typical destination bachelor party expenses would amount to 51.2 percent of this amount, while the average bachelorette party expenses would use up 37 percent.

"Buying a home is one of the most expensive purchases someone will ever make, and for most first-time buyers that means saving money to afford a down payment," said Jeremy Wacksman, chief marketing officer at Zillow. "Attending your friends' bachelor or bachelorette parties can be a trip of a lifetime. While everyone's budget and priorities are different, big ticket expenses like vacations can add up surprisingly quickly – a lot faster than a $19 avocado toast."

Wacksman's comment alludes to recent remarks by Tim Gurner, a 35-year-old Australian real estate magnate and millionaire. Gurner criticized the spending habits and expectations of younger generations in a "60 Minutes" interview, saying that when he was trying to buy his first home he "wasn't buying smashed avocado for $19 and four coffees at $4 each."

Per the values supplied by Zillow and The Knot, a person would have to consume nearly 394 of these $35 meals to equate the average cost of nine destination bachelor parties, about 284 meals to equal the cost of nine destination bachelorette parties, and about 1,145 meals to equal the down payment on a median priced home.