well right off the top of my head, you'll want to be using a database to store the info, given the simplicity of the program an MS Access database would be fine (Access comes with MS Office, just like word and excel) so researching databases with vb.net would be a good start
as for the actual program, you'll probably want to have it so you can enter an amount recieved, then have it display how much will be bugetted to wherever it goes, i cant be anymore detailed than that because i'm gonna leave that up to you to think about
but you should make the program be able to add different "budgets" meaning the user should be able to add a new item to the list of things that needs to be bugetted for
i hope that helps ya some