Over the past few months we've shown you a couple of network-attached storage (NAS) devices selling at two rather distant price points. The 8-bay QNAP TS-809 Pro Turbo, you might recall, offered the highest levels of performance, but carried an equally imposing starting price of $1,700, escalating up to around $3,000 when equipped with eight 2TB drives. Obviously, this device is targeted at businesses that have that kind of extreme requirements.Then we had the 4-bay Synology Disk Station 409+, priced at $600 without hard drives, which might come as a more reasonable choice for the home or small office, while still delivering good performance and a compelling feature set.There are a number of legitimate reasons why NAS devices are becoming so popular in work environments, but because of the costly setup investment, they have remained more of a luxury than a necessity for home users.More affordable products are finding their way to the market all the time, however you should be wary with some of them. For example, one of the cheapest 4-bay NAS devices available right now is the Promise NS4300N SmartStor at just $290. I made the terrible mistake of purchasing this product because of the attractive price point alone. The result was average performance, worsened by a nightmarish setup procedure and overall poor functionality that was plagued with issues. Turned out it was not only the cheapest, but also the worst 4-bay NAS device money could buy.