Is it a good idea to start playing with open source projects for beginners?

[sherkhan345]

I m going to create a software for small business (Store), which will have to print invoices, keep track of stack, but all data will be entered manually by only one user.
I know basics of all programming and markup languages including OOP
C#, C++, Java, HTML, CSS, PHP, ASP etc but I prefer C#.
should I start searching for open source software? because i don't know where to start? So I will get into the code of open source software to get some idea from that.
If yes, Please recommend me any open source software.
Tools I Prefer:
Visual Studio
SQL Server

[pandu13]

Yes, you can work for open source projects

check apache official website for projects contribution

http://www.apache.org/