I've had my LA since Sept 2007. I had a heart attack and quad by-pass in Oct 2007. The next year, I never touched the machine. I couldn't even lift the weight of a queen size quilt much less stand to quilt it. There's always a learning curve on a machine. You need to take alot of things into consideration. Like, is it going to be free motion or computerized? (A difference of thousands of dollars in initial purchase price.) If you are doing free motion, plan on spending many hours to get used to using different weight threads, learning the speed that is right for you and using pantos. I don't think it's something that you can just walk into and plan on quilting for someone else unless you are stippling. Even then if you go too fast, your bobbin thread will be bigger on the bottom. It's all about control. (Ask me how I know. LOL)
If you are serious about doing quilting for others, there is always a need. After your sure that you can do different stitches, make up a baby sized quilt showing the different stitches that you can do. Join quilt guilds in your area and keep the sample in your car. Bring it up in the meetings that you do long arm quilting, show your sample and let it go from there. Word of mouth is your best advertisment. Make sure you research LAQ in your area for their pricing so you can compete with them. Also make sure than you only take in what you know you can get done in a reasonable time. Check with your homeowners insurance for coverage on property of others in your possession.