Elvis
The best answer would be that you need the licence for the job. Therefore either achieve it here or go elsewhere then convert, unless elsewhere is in JAA - but last I heard the only English-speaking JAA school I know of outside the UK now only offers integrated courses (see other threads - I shan't open that can of worms here). If you convert then the cost ends up similar, the timescale much greater - losing on the swing your roundabout gains.
A common option is to do part - PPL and/or hour building in the US, Canada or the RSA, then the approved courses in the UK. However it can take a while to get aclimatised (or re-aclimatised) to British operations, often extending the CPL course (which many find quite tight anyway at 25 hours) and costs there take back some of the gain. If you can find a good block-booking deal in the UK you may end up gaining little but a tan from going to Florida, and American beer is a lot to put up with for small savings!
I do however recommend you look seriously at the part UK/part overseas option - it is a good compromise for some people.