So Yes it does require you to code in Unreal engine, there are two methods in which you can code.
- C++ Coding Language which uses Visual Studio in order to code.
- BPS(Blueprint Script) This is a drag and drop style of programming which will require you to have a understanding of logic.
Also No it doesn't cost any money to create on unreal unless you are making and selling games via a market like steam I believe. I am not sure on that.
Though it is totally free to create again unless like I said above or your paying to buy assets from the market. If your interested in creating in Unreal you can download it from the EPIC website via the epic games installer.