My Girlfriend has completed her bachelors degree and we are currently looking at her coming to UK to live with me or do her masters. However, I am torn between Fiancee visa or paying for the masters then apply for spousal visa at some point during her study. Just exploring the best option for us and also which option with minimal cost effective even though they all come at a cost. Shes in Ghana but we've been on a number of holidays. I am british. I earn 39k + 15% bonus a year = 45k. What would you kindly advise.
You do have a range of options. A Study Visa may be a good option if your girlfriend has been accepted into a UK tertiary institution for her masters. If she enters on a Finacee Visa you'll need to get married (or enter into a civil union) within 6 months of her arrival in the UK. Your girlfriend will not be able to work on the Fiancee Visa.
To see more details on the Student Visa and other options this page on UK Visas may be helpful.