AS more brides try to sell their used designer wedding dresses online, some have found a way to stand out from the competition: putting their wedding dress up for sale before even walking down the aisle.

Would you presell your wedding dress or other wedding paraphernaliad?
A growing number of postings for so-called presale wedding dresses have popped up among the listings on sites like preownedweddingdresses.ca in Canada or oncewed.com in the United States.

The founder of preownedweddingdresess.ca, estimated that there are close to 50 such postings on her site, up from just one 12 months ago. The owner of oncewed.com, expects 25 or more presale listings on her site this year, up from none two years ago.

One reason for the high prices is that the brides selling the gowns often spent far more than they had originally planned and hope to get some of the money back — quickly.

Kourtney James, 30, a lawyer in Houston, had budgeted about $1,500 for a wedding dress but fell in love with an Angel Sanchez strapless gown that cost $3,300. Now Ms. James, who is paying for her wedding with her fiancé, hopes to sell the dress for $1,650 before her August wedding. “If I can secure a buyer before the wedding occurs, it takes a lot of the pressure off,” Ms. James said.

A used wedding dress generally sells for about 50 percent off retail, whether sold before or after the wedding. But brides see an advantage to selling before the wedding because the styles are still current and other brides often can try on the same dress in stores. That, they say, enhances the likelihood of a quick sale.

“I know it’s a very popular wedding dress right now, and I didn’t want to miss out on the fact that it’s a hot ticket,” explained Erin May, 30, a marketing director in Seattle whose wedding is not until August but who quickly sold her Vera Wang Diana dress for $4,650 after listing it online. She said she paid a little more than $7,000.

Yet, as anyone who has ever had a garage sale knows, putting a price tag on something is one thing, and finding a buyer is something else.

Zofia Gajdamowicz, 27, a bartender in Toronto who hopes to sell her Modern Trousseau dress before her wedding in late October, said she will “have to be a little more careful” if she finds a buyer.

“I already told my friends, ‘Don’t let me drink any red wine,’ ” she said.