In the creation window you can select Beginner gear, Veteran Gear, and No Gear. How about a 4th option that lets you see what your created character would look like wearing a costume available in-game? This way the player can customize their characters around the costume they would like to use rather than trying to figure out after creating the character what a costume would look like on them. It should show all costumes currently available, not just the ones you own, this way if they pick out a costume they don't already have and enjoy the look of it with their newly created character, they may buy it.