You must pay for VS professional. You can download VS community for free. No one is going to give you a license for VS professional, it is not a cheap piece of software.
VS Community 2015 is too heavy. Is there any other C++ compiler which can fulfill the same role as VS Compiler Community without taking too much space?
Well Visual Studio Community is the whole IDE, not just the compiler, but there are a plethora of compilers and IDEs to choose from.
More minimal compiler + IDE options are Code::Blocks + MinGW