To save your current Budget, simply choose Budget > Save or Budget > Save As... menu. If needed a Save dialog will be display to let you choose the file name and the place where you want to save the file. The extension for the Budget files is BBB which stand for BlueBrick Budget, but the format is XML.
In the title bar of the application, you can see the name of the current Budget (if any is opened) next to the name of the current map. When your budget has some unsaved modification, a little star will appear next to its name in the title bar.
It is very easy to open a previously saved budget file or a budget file you may have received from your friends. Simply choose the Budget > Open... menu and select the BBB file on your disk.
Note that if you have created a budget file for your own LEGO® collection that you always want to use when you create a new layout, you can tell BlueBrick to load that file automatically at startup. To do this, go to the Edit > Preferences menu and choose the Part Library tab. Read the Part Library Preference section to know where to specify the budget to load at startup.
Moreover, if you are the coordinator of a collaborative project, you can ask all the participants to send you their budget file corresponding to the parts they can bring for the project, and merge all of them into one big budget for the project. To do this, create a new Budget ( Budget > New ) then import each budget file in this new Budget by choosing the Budget > Import and Merge... menu, and finally save the global budget in a new file ( Budget > Save As... ).
If you don't want to use the current budget anymore, you can close the current file by choosing the Budget > Close menu. If you have unsaved modifications, a message box will popup to ask you if you want to save it before closing, and of course you can discard the changes if you wish.