The starting point when saving is likely to be building society. With an account, you'll usually get back the amount you put in plus a bit extra in interest. This means they are a low-risk way to store your spare cash. This risk is the key difference between saving and investment products.
Although held in savings is generally secure, the impact of inflation will reduce the buying power of your over time, unless the growth you receive through interest is at a higher rate than the rate of inflation.