You are probably aware, when you leave your country, and are making phone calls you are paying huge amounts of money. You can cut costs by VOIP calling when in an Internet Cafe, but even that's not very convient when you're walking around town, or in a hotel, and want to call people.
That's why I bought myself a Lyca Mobile prepaid simcard for £5 this weekend. I only thought they had calling cards, but they actually have their own SIM cards!
I was able to call to Netherlands for as low as 4p to landlines, and 16p to mobile phone numbers. Texting costed me 9-10p per SMS.
Will keep the card for my next visit in March.