Normalise an expenditure table in a budget database
Assuming they all have the same three columns you mentioned an no more, have you considered this:

expenditure_budget_item:
id | type_id | amount | frequency | comment
30   6         50       null        "test comment"
31   7         40       null        null

expenditure_budget_types:
id | name   | description
6    "Food"   "Food expenditures"   
7    "Fuel"   "Fuel expenditures"


Let me know if there's any details I may have missed.