If you are interested in purchasing a dehydrator, I'd go with nothing less than an Excalibur brand. The design is heads and tails above anything else (especially the round, stackable ones) and they will stand behind it forever. A friend had one that a thermostat gave out after 15 years and with one phone call they shipped her another thermostat no charge. It doesn't matter if you bought the thing third hand on eBay, Excalibur will go a long way to assist you with outstanding customer service.
Excaliburs come in several different sizes. I have the largest model that is not commercial. I started with the smallest one and used it so much for so many different things that I upgraded within one year.
Cabelas also sells a very good dehydrator, but the price is a bit higher than an Excalibur. If I ever decide to get a slightly bigger unit, I will probably go with Cabelas.