Got it, I managed to get their budget up to $40 like I told you before.
I got two projects for you at $40 each. So it's $80 for both.
3.) Currency Converter
4.) Program to track and split money and items among friends (Its very simple actually If you dont require sync. Syncing would be tougher to implement, but they can do without it)
Here are some guidelines you have to follow for both projects.
1. An Appropriate GUI should be used.
2. The Application should use Inheritance.
3. Data should be encapsulated appropriately.
4. Exceptions and errors should be handled
5. Demonstrate reading and writing into files. (.txt files)