Remember that a lot of places in Bangor, the rest of the UK and overseas will offer a student discount - don't be afraid to ask! Some places will accept your Bangor Student ID Card, however the NUS Extra Card is more widely accepted. If you will be travelling outside the UK, then think about getting an International Student Identity Card to get cheap deals around the world!
There are several websites that search the UK for special deals, including MoneySavingExpert. To find other similar websites you could try an online search for "travel discount codes" or something similar depending on your travel plans. There are also several mobile apps available, just search "discount codes" in your app store.
School Holidays and Bank Holidays
Many tourist places (particulary family-friendly places) may offer discounts during school holidays, especially February and October half-term. However, these places are likely to be very busy during these times.
The Bad News... Because it is the holiday season there may be less cheap deals available. Flights and accommodation are likely to be more expensive.
School holidays in Gwynedd (Note: Not all schools in the UK have the same holiday dates)
Bank holidays