Some studentships/scholarships are available for Masters courses, but they are few and far between and usually only cover part of your expenses/fees. If you apply for any Masters courses ask about funding availability. You may also find that scholarships exist for people from your particular area of the country (contact your local education authority to see if they know of any schemes).
A CAST Award is given when the PhD is in collaboration with an industrial partner and usually pays a few thousand pounds more per year. In most cases the student is based in a university, but may spend several weeks or months using the facilities of the industrial partner. These studentships are advertised in the same way as any others - through FindAPhD, on university web sites and in the scientific press.