The cheapest way for what you are looking for is to find the nearest craft/hobby store and buy the blank hoops and the letters you need...Then sit down for five to ten min and ta da you're done...
Also, there are a couple things -- many people make jewelry, maybe try craigslist for your area for someone who makes jewelry? It sounds like you want hoops with either lettering charms or one charm with slave on it. I am sure an amateur jewelry maker can do so.