Fed up with paying extra for calling numbers starting with 084 or 087 on your mobile? This is a problem on all networks, even if giffgaff's 20p per minute is more reasonable than what some other networks charge. The good news is that in most cases you don't have to call these premium numbers as there is usually an alternative geographical number that gets you through to exactly the same place. The best place to find these is on this useful site http://www.saynoto0870.com/search.php
All you need to do is enter the 08 number you want to call and a list of suitable alternatives will be provided within moments where available. If you've discovered your own elsewhere you can also submit it to the database if it doesn't exist there already.
Remember that Freephone numbers (0800 etc) are FREE on giffgaff (unlike on other networks) so you don't need to find alternatives for those!
you can find all alternative numbers for such as 0844,0845 and 0870 and you can find local numbers starting with 01,02,03 or starting with 0800 free from landline. Just go on this link Put the number or company name in the relevant boxes
From my research the best alternative numbers are the 0300 numbers as these are included in yourn free minutes bundel (typically 0800 numbers aren't free from a mobile except with giffgaff).
This website http://savvycaller.com/ seem to have a lot of 0300 and 0800 alternatives for some of the big brand companies.
Hope that helps.