Unity3D has a ton of free material that you can use to create games.
https://www.assetstore.unity3d.com/en/#!/search/page=1/sortby=popularity/query=category:0&price:0-0
This is a list of 1300 free 3D model packs that Unity3D offers in its assets store. There are also scripts for game behaviors, shaders, textures, you name it they have it and its free. You can learn and work with these until you have the confidence to invest your money in your ability.
Be a Man with a Plan. Please not this will take time, but at the end of this process you will feel duly and truly prepared to take on your task. You will not be an expert by any means but you will have the tools the begin creating your vision!
Step 1.
Learn the unity interface
Complete the first 10 tutorials in the link above.
Step 2.
Introduce Yourself.
Unity3D's greatest strength is its community. Make it your strength as well.
Step 3.
Learn to express yourself
C# is the scripting language of choice and microsoft will teach you basics for free.
Step 4.
Build under direction of a master.
Check out the Unity3D project tutorials. Don't just skip to the kind of game you want to make. These tutorials give you an idea of what the engine is capable of in different applications and help you develop technical skills with the engine.
Step 5.
Don't stop when the tutorial ends.
Tweak the games and change them as much as you are capable. BREAK THEM and then repair them. Have fun with them!
Step 6.
Identify your strengths as a developer and run with them.
Supplement the rest with tutorials by now you should have an idea of what you need. Keep learning and keep building. DO NOT SWITCH ENGINES. DO NOT SWITCH LANGUAGES. Plow forward with the strong base you have and BUILD.
Good luck man. I hope you decide to start learning Unity3D today!
-PowerMan