Today I popped to a local charity shop. It's one I've identified as a good place to buy school uniform. They have two big boxes in there at the back all year round and I've discovered it's worth having a look every few weeks. This time last week I managed to pick up several school dresses for soph, and several skirts. I had to buy her school grey pinafore dresses new from Tesco (but I used club card vouchers, which were on a double up scheme, as I used ten quid worth, doubled up to twenty, and got three dresses), but I didn't buy any of the skirts or summer dresses or the tshirts new, but got them all at fifty pence each mostly from that charity shop.
There's a drawer under my bed which is where I store out of season uniform (so currently, grey dresses and skirts, grey tights, and the cardigans which go with those dresses. Sophia has one drawer in her room for uniform, so currently she's got the summer dresses, lighter weight cardigans and white socks in there. Additionally in my under bed drawer I have summer dresses in a bigger size, and some skirts in a bigger size, as well as the tshirts which are in a variety of sizes, and extra PE kit, all purchased in charity shops at fifty pence each.
Today I bought six items in the charity shop, one is a pair of shorts that will fit jj now, two pairs of bigger shorts, two trousers for JJ and a skirt that will fit soph in a couple of years. Because I'm willing to store some things, and spend a little now, I am able to plan ahead and avoid big spends when my kids get bigger and need new clothes. I can shop in my drawer rather than the high street!
I'd really encourage you to do this if you can. (happy to share my shop location with local folk!). This principle can be applied to all children's clothing really, but school uniform is a biggy, in my opinion, cos they have to wear it. My other tip would be to buy the more expensive brands. Most all of JJ's trousers are from M&S or next, Soph has clothes from M&S too. I also made sure that I check the, over for wear - particularly at the crotch and knees for boys! And, I'd advise keeping a running list of what you've got already, so you don't end up with too much in one size. Final tip, if you do have too much, or your child outgrows an item before it's worn out, consider gifting to a friend with smaller children (not necessarily younger!), passing on to the school as spare stuff, which is particularly in demand in the younger years, or selling on your local Facebook group to make back your money.