Hi,
Organising a budget on mindmanager works pretty well except there are no functions for the custom types ...
Say each budget item has an "estimate" and a "cost" custom property (type currency), then if parent items could have a function property that totals the estimates and costs of it's children all the categories and subcategories in the budget map would have automatically populated values, which would be really useful.
Adding more general functions means you can start creating tree-like spreadsheets too.