Using Mobiles in France to call home

Good afternoon everyone!

I have received the following question from a member:

What is the cheapest way to phone England from France using mobiles?

I use a 5 year old pay-as-you-go phone, so am not up to date with phone technology at all!!! So any suggestions or help would be appreciated!! :) Should you buy a new sim? Contact your current provider? Use phone cards???

Thanks

Hazel