First, to answer your question about which kind of calls even a beginner can use....how about a Knight & Hale push/pull rod call. It is basically a small box with a spring-loaded rod you can push to make yelps. It is probably the simplest of all calls to use. It could be a little higher pitched, but makes decent yelps. Next, there is Knight & Hale' s Lonesome Hen. Another push-pull rod call which I have used and called turkeys in with. So simple, my son was able to make good calls on it when he was only four.
Then, with some practice a beginner can master friction calls i.e; box calls and slate, aluminum, or glass calls. The key is to get started early and master at least three different types of calls. The reason is because you want to be able to take a couple of different calls into the woods to use. By doing so, you can sound like there is more than one hen to fool those gobblers. Learn to keep the striker on the slate surface and make circular motions to make the basic yelp.
Finally, you want to attempt to master these three turkey sounds: the tree yelp (a softer version of the basic yelp), yelp (basic hen sound), purr (contentment), cluck (feeding), and cutting (excitement). You can hear all of these at
http://lakewashnwtf.tripod.com Just visit the " turkey sounds" page.
Finally, and this cannot be stressed enough! Learn to not overcall. Limit your calling to about every 20-25 minutes. Don' t move and be patient! Be willing to log in some time in your spot. Your butt is going to get sore, but success never comes easy. Patience, patience, patience!
Hope that answers all of your questions.