Student Union shops
If your university has a central student union building, then it might have shops where you can buy things for less than you would pay on the high street. As well as things like food and stationery, many student unions have hairdressers and other services to help students to save cash.
Some companies and shops will give you money off simply because you are a student. This is normally around 10%. However, for some things, the discount can be much higher. In particular, expensive software like Microsoft Office is often much cheaper for students to use. You'll normally need to show a student ID to get the discount in shops, or register with your university email address if getting a discount online.
When buying tickets for cinemas, theatres or events, you might see a separate price given for 'concessions.' This normally includes students.
Not all shops advertise their student discounts, so it's worth asking if you're not sure.
NUS Extra and ISIC
Although many student discounts are available to all students, you can get access to extra discounts with an NUS Extra card or an International Student Identity Card (ISIC). You can get an NUS Extra card for £12, an ISIC for £9, or a combination of both for £14.99.
There are a number of websites that can help you to get discounts. Websites like VoucherCodes let you search for money-off vouchers for any shop, or browse for the current best deals. Others, like Groupon, let you buy particular products at a reduced price each day. This can save you money as long as you don't get tempted to buy things you don't really need just because they are discounted.