While working for a fashion retailer as a university student for two years until 2016, Ms Thompson, 21, said she was expected to be wearing clothes from the fashion label's latest range.

"You needed to look like you were wearing something new," she said. "You were expected to not be wearing the same thing every day.

"The idea was that if you look good in something, people come up to you and ask, 'what's that?' "

A new University of Sydney study has found that relatively low-paid retail workers are spending thousands of dollars out of their own pockets to promote the fashion brands they sell.

The study by Leanne Cutcher from the University of Sydney business school and Pamela Achtel from the Leading Edge Australia found this had led to resentment in close to half the retail workers. But more than half, seemed happy to continue spending their own money on the merchandise they sold, because many saw themselves as an "extension of the brand".

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Professor Cutcher said it was unfair of some companies to expect people in relatively low-paid jobs to buy expensive clothing to model the brand they were selling. She said retail staff should ask prospective employers how much they expected them to spend before accepting a new job.

"With some of the stores the employees couldn't even buy things on sale. Everything had to be current," Professor Cutcher said.

"Only one store had a rack of clothing out the back that people could put on for the day."

The university study based on interviews with female and male employees from 16 major retailers in Sydney found employees were spending a large portion of their wages buying merchandise to wear at work, often with little compensation from employers.

Staff discounts ranged from 0 to 55 per cent.

One retailer offered one free outfit per season.

Outfit costs across the retailers surveyed ranged from $105 to $1150, and included items such as shoes, underwear, jackets, ties, jewellery, belts, and hair clips.

Ms Thompson, from Beecroft in Sydney's north, was studying communications and public relations at the University of Technology when she worked at the fashion retailer.

She said staff were offered a 35 per cent discount off retail prices.

"Every three months were were given $110 to spend on the most recent season's clothing, but it didn't go far," she said.

"We weren't forced to buy anything, but every now and then you would get comments like, maybe you should get that dress.

"Because it was my job to get through uni, I didn't have a massive disposable income to buy clothing I would not wear again."

A spokeswoman for the clothing brand said it was not compulsory for retail employees to wear the brand at work. However, employees were encouraged to wear the brand where possible and were provided with wardrobe allowances and discounts to assist them.

"Depending on their frequency of work, our retail employees are provided with a wardrobe allowance of up to $1,100 annually," the spokeswoman said.

"On top of this, employees can use their staff discount of either 35 or 40 per cent (depending on whether they are in a casual or full time role).

"Ultimately, we find that our employees are passionate about the brand and enthusiastic about the product so while there is absolutely no requirement, many choose to wear [the brand] because of the affinity they have with the brand and we offer comprehensive employee benefits to help make this possible."

Ms Achtel said the study, which has been published in leading international journal Work, Employment and Society, found employees were more engaged if they were given some freedom in what they were required to buy for their "work uniform". Prescriptive dress codes and disregard for an employee's personal style had led to "disenchantment".

"Wearing pieces that fit into the employees' own personal style, and having fun with the brand really feeds employees' confidence, and this is communicated to customers in the store", Ms Achtel said.

"While brand guidelines may be created in head office, it's the frontline staff that live and breathe them while interacting with customers."

Priscilla Fujita, 23, from Sydney's inner west, was studying speech pathology at Macquarie University when she worked for a major cosmetics retailer until earlier this year.

Ms Fujita said she spent up to $2500 of her own money on cosmetics in the two years she worked for the cosmetics brand.

"If you were a full-time student, you didn't have any extra money and it was quite expensive," she said.

"I was given an allowance of roughly $80 per month, but I spent up to $200. This was completely up to me."

Ms Fujita said she received a 40 per cent staff discount and was expected to wear black tailored clothing, which she bought for herself.

"You were expected to be on-season and your make up had to be representative of the products we sell in store and that are in stock," she said.

A spokeswoman for the cosmetics company where Ms Fujita worked said staff were required to "maintain personal grooming standards that befit" the brand. She said there was no reason why an employee would need to spend $2500 out of their own pocket to be "work ready".

"Staff have access to all in-store products for use prior to commencement of their shift - there is no requirement for staff to purchase products for use in work hours," the spokeswoman said.

smh.com.au