I would get some cheater tops and just freemotion quilt on it. Using the cheater tops will give you the same focus you will need later on a "real" quilt, but without the time and expense. Use muslin on the back, and the least expensive batting you can find. Here's a good site that has reasonable prices and a good variety of different tops:
http://www.pre-printed-quilt-tops.com/
I bought my long arm online, and didn't even have ANY training on it. This is EXACTLY how I began learning, and I still do this when I have a new tool or have heard about a new technique and want to practice.
Look for some quilt tops at yard sales too - this is another "cheap" way to get your feet wet and also allows you to get the feel of going across seams and dealing with "non-square" quilts. Both of those are problems you will encounter later on, and it's a lot less stressful learning about them on a cheap top rather than it be something you've already spent a lot of time on (or even worse, a customer quilt from a customer whose seams were quite less than perfect, but who expects you to "quilt that out"). Relax, have fun, and jump right in!! And from what I've heard, most dealers will help walk you through most any questions you have over the phone.