How to make an 'Orange' phone accept a 'vodafone' sim card?

I broke my phone the other week, and since then ive not had a replacement. Im on contract and it doesnt end till september but i've already sent my phone for insurance repair before and if i keep doing it i doubt they will trust me to have an iphone nect uprgrade.
So today my friend lent me a phone, but it is an orange type phone, well it is samsung make but has the 'orange' symbol and doesnt work with my vodafone sim.
Does anyone know a way to convert it?
My mum said shops do it for like £20 but i really dont have any money and nor does she. So please help? is there anyway to do it, how much does it cost in shops aswell because she might be wrong? Thanksss! From uk if that matters...