Schools in Wales are being urged to have uniforms which are more affordable, accessible and gender neutral, by new statutory guidelines.
Previous 2011 guidance from the Welsh Government was non-statutory, meaning schools were not legally required to have regard to it.
The changes will come into force from September.
Parents will be able to make formal complaints to schools that do not take the guidelines into account.
The government said ways of reducing the costs of the uniform could include stipulating basic items and colours but not styles, which would mean clothing could be bought from different shops.
Whether or not school logos were "strictly necessary" and if uniforms needed to differ for summer and winter were also points expected to be considered by schools.
A consultation was launched last autumn following the summer heat wave, in which some parents claimed that uniform policies were too strict.
New policies are also expected to be gender neutral, meaning that items like trousers would not be described as "for boys".
Julie Ann Richards, whose daughter is a pupil at Ysgol Gyfun Garth Olwg in Rhondda Cynon Taff, said the current cost of a new uniform for a single parent like herself was prohibitive.
The school, and its primary feeder school, will be closing at the end of term and re-opening as one school for three to 19-year-olds - with a new uniform, which Ms Richard expects to cost about £200.
"For me, as a single mother, that is a lot of money and it means the difference between a holiday this year or not," she said.
"I'm worried about those parents who have more than one child at the school," she said.
Trystan Edwards, the head teacher, said there were numerous suppliers available to parents to purchase uniform.
"As well as that, there is a transitional year for the first year of the new school, and an additional year for PE kit, and therefore there is ample opportunity there to be using existing uniform.
"We have also set aside some funds to give assistance to all the families claiming free school meals, but also those who are on that poverty line who wish to have further assistance," he said.
Mr Edwards said that in general the new guidelines were to be welcomed.
But he added: "It's very difficult for us to react, and be mobile as far as governing body approval, to such guidelines so late in the academic year.
"We could have done with this in midwinter in order for us to prepare as schools."
Education Minister Kirsty Williams said it was "signalled a significant time ago what the Welsh Government intended to do".
She explained that school leaders and governing bodies will still decide their own policy, but added that they will be required to take the issues of affordability into consideration.
Ms Williams added that parents will be able to make formal complaints to schools if they feel that the guidelines have not been taken into account.
Mother-of-three Sarah Hoss, from Pembrokeshire, said the new guidelines were "a really good idea".
"I think so many parents struggle when you have to buy the official uniform... It's frankly ridiculous because the price is very, very different."
She added: "In my case there were no hand-me-downs to be had because they were all in separate schools and there was a big age gap too."
Through the pupil development grant, the Welsh Government provides £125 for students eligible for free school meals to buy uniforms and other equipment.
Eligible year seven pupils are also entitled to a grant of £200 to help with the costs when beginning secondary school.