The cost of a quinceanera is growing all the time. Even when done small scale, you may find that you can't cover all the expenses. It is tradition to ask padrinos to sponsor portions of your quinceanera. Or they may offer to do so.
If you are asking padrinos to sponsor portions of your quinceanera, be sure to let them know exactly what you need and give them an opportunity to bow out gracefully if they can't help. Most family members are happy to help with a portion of the event. An abuelita might buy or make the gown, an aunt might pay for the cake.
Recognize all padrinos and sponsors in your program and your thank you speech. You will also want to be sure to send them a very warm and gracious thank you note as soon as possible.