There is also mechanical robustness of the more expensive cables to consider which could be an advantage. What I mean is that if you get a very cheap cable then the quality of joints & the connectors could be poor. If you pay more than say £5 then you will probably get a cable that will last a lot longer and also fit into sockets without falling out or making bad connections. Something like this should be all you need as long as you are not going for long cables.
http://www.amazon.co.uk/gp/product/B0019JPMJK