Possible Clues:

• Study in guesthouse, say, to make a living
• Doughy pre-dinner duo
• Keep food for sandwiches
• Basic study covered by group banned at first, say
• Main thing
• Bit more than a crust earned?
• Money band wasted, say, providing basic source of income
• Chief source of income, metaphorically
• Look at occupying B&B, say, for livelihood
• The baker on the farm made ..