First, you need to schedule an appointment ahead of time or else you'll find you self utterly bitter for having leaving without any pretty nails on.
Second I suggest bringing in your own ideas or just picking out something you like in their Facebook page or instagram. You can even bring in other people designs and they'll match it.
Lastly if you get what you pay for. I don't suggest expecting everything under the sun done to your nails and only paying $20. You're getting quality nails that last.