1. Leggings- You seriously cannot go wrong with leggings, whatever the weather, they are a life saver... As long as they aren't see-through! They work best with long t-shirts or jumpers, and can be layered up or down depending on the weather. I buy them from primark for around £3 per pair.
2. Jeans- I would recommend light ones because they work better if it's hot out and they keep the outfit bright and colourful rather than just dark. In summer you can roll them up and pair with a t-shirt and for winter mix with jumpers or a coat and boots. These jeans are from Forever 21 for £7.99.
3. T-shirts- These are the best all season clothes, they mix with everything and of course they can be really cheap! Thy tend to be around £5 to £12 depending on where you shop. Wear them under jumpers in winter and just on their own in summer.
4. Skirts- If you want something a bit more interesting in your wardrobe then skirts are perfect! If it's hot just pair with a t-shirt and if it's chilly out, wear tights and layer up on jumpers. Mine is from H&M online for £6.
5. Shorts- Basically the same concept as a skirt.
6. Tights- They are multi-purpose. Under trousers in winter or with skirts/shorts on a cold summer day. Usually around £3-£4 for a pack of them in any supermarket.
7. Cardigans- you can pick up cardigans for like £3.50 at primark and they are as good as any other. They can be used as layers or just to cover your arms in summer.
8. Jumpers- I find zip-up hoodies are the best because you can layer them up in winter or leave them unzipped in summer. They can be anywhere from £6 to £20 but I find they are normally the same quality-wise, so the cheaper the better really. Buy one in a neutral colour so they mix with everything.
9. Coats- A long coat to throw over anything when it gets cold is what you need to look for here. Go for standard colours so it doesn't clash. Parka's are a good shout because they are fashionable, and are available in most places for a good price. I bought mine last year from Matalan for £35.
10. Shoes- Trainers like vans or converse are good durable shoes for any season and I find that you can buy them new online (Ebay or Amazon) for almost £10 less than in shops. But if you want something more, go for boots like these ones from H&M (£24.99) for winter.