I'm using Visual Studio to develop my automation. But unfortunately, we need to pay for it (no pay no gain ).
Is it possible to use for example Sharp develop to automate SE?
You can use Visual Studio Community, it is free.
You can use it to develop your apps in Visual Basic and C# and export your macros. You can sell them if you want: http://stackoverflow.com/questions/32448921/can-i-use-visual-studio-2015-community-edition-for-my-so...
Visual Studio Community License Terms
It seems possible. I am able to add references to the Solid Edge framework and access a running instance of SE. No support for intellisense out-of-the-box, so perhaps I am missing some setting: