Oxfam is appealing for more second-hand wedding dress donations because demand at its bridal outlets is booming.
Louise Manfredi bought her wedding dress from Oxfam for £129
The charity runs nine dedicated bridal stores in England, with an average wedding dress price of about £250.
It said more brides-to-be were seeking a cut-price option in order to give their big day a more "ethical slant".
The charity's need for more stock was highlighted by the month-long waiting list for appointments at Oxfam's bridal shop in Eastbourne, East Sussex.
Barbara Warmsley, the charity's bridal co-ordinator, said: "It's great that so many brides are coming to Oxfam for their dresses, but we are desperate for donations to meet this growing demand.
"If a donated dress sells for £250, this can provide 100 people with clean water, build two toilets, train one midwife and feed a family for a month."
A survey of 600 people found that 82% of brides still had their wedding dresses stashed away, prompting Oxfam to appeal for more to be given to charity.
Louise Manfredi from Chesterfield, Derbyshire, bought her dress for £129 from the charity's Heswall store, in Merseyside.
She said: "I would recommend that anyone who is getting married, especially those people with tight finances, take a look in Oxfam before spending hundreds of pounds on a dress."
Rosemary Tyndall, who donated her dress to Oxfam's bridal outlet in Shirley, Southampton, said: "I love the fact that something which was so special to me is now being used to help other people."