Do not give up your day job. I've been at this 5.5 years now, and just went full time last June. Until then at times I thought I was working 3 jobs and only getting paid for one, however, an education does cost money. I figured my first 2-3 years was just that...an education.
Every states rules differ a little. But, I think there is no rule that says you have to do appraisals under a supervisor...as long as those appraisals are for no one but you and your state certification process. Here's how you can gain some hours, but there is no pay and no boss or supervisor.
Get a computer, a digital camera, take the appraisal classes, and get some appraisal software. (some software you can get on 30 day free trials...try several before you make up your mind.) Join your local board of realtors as an affiliate member. Get the MLS books. Go to an open house, explain what you are doing. Write an appraisal on this house. It goes no where but your file. Do a couple, then call an appraiser and offer to buy lunch if they would critique your work. Take your work back to one of your appraisal class instructors with the same offer. Suggest you start with the 2055 form...do several then progress on to the 1004. The 1004 is a ittle more complex in filling out. Each of these reports ought to be worth 5-10 hours of experience. My 1st 3-4 reports I know took 20 hours each. 5 hours was getting chewed out for making mistakes, 5 hours was spent driving back to the inspection site and comps 2 or 3 times because I overlooked something. I bet if you did enough of these, you could walk into an appraiser with some completed reports and they just might pick you up as a trainee, because you have already proven you can stick to it and you are determined. Better you help them, than their competition.
Good luck!