As you can see on your little profile by your topic/post, you have an area that says "ryo" with a number next to it. That is the money that your character has, that you can earn by advertising, posting in certain areas, and doing missions. Based on how much money you have, you can level up, earn more abilities, and/or enhance your character in other ways.

There is a shop section that you can go to here!

If you have any questions, feel free to ask.