Free Running had an interesting post where I found the following description of different ways of categorising value for money:

• It’s a SNIP when: You are offered a discount off the shelf price.
• It’s a STEAL when: It can never be found cheaper.
• It’s a BARGAIN when: It’s cheaper than last week.
• It’s GOOD VALUE when: It’s unique and seems to be offered at the lower end of the available price bracket rather than the at the highest price the market can hold.
• It’s a GOOD VALUE BARGAIN SNIP STEAL when: It’s been smuggled!