You can easily come up with a great plastic cards design, get the plastic cards printed and delivered all in less than a week. In fact, some websites offer next day delivery on many business card designs they print.
Now, if you really want to start from scratch and create your own plastic card design on your computer, here is some information that you'll find helpful. First, locate the plastic cards printer you will be using and find out what file types they will accept and at what resolutions. You will also want to learn about their charges for bleeds, spot color and process color. These things also have specifications that must be obliged such as how wide of a margin for a full bleed. A standard finished sized plastic card design is 3½" x 2". Some printers require a properly formatted and spaced gang; others will accept a single piece of artwork. If the printer you select has a template available, using it will simplify your task.