Is the cost of a lease on a home much less in Cardiff as in Southampton or Portsmouth? Are job prospects better? More higher education?
Use numbeo.com to compare cost of living. For an idea on housing costs, you can look at various websites, including craigslist, to get some ideas for comparison in addition to housing ranges listed on numbeo. As a foreign student, count on NOT being able to find a job as most foreign students do not, even if terms of the student visa for that particular country allow limited work. Furthermore, to qualify for student visa, you must prove you have sufficient funds for all school + living expenses + return transportation to your country of citizenship. But do note unemployment rates in Wales far exceed those elsewhere, e.g. England. Your chances of finding a job are especially poor.