If everything checks out with this carpet, and the seller entertains your request for photographs, I think it's an okay investment providing that there are no significant variations in the length from either side, or previously mentioned problems.
As for the price on these rugs, I cant say for sure why they're inexpensive, but I gather it's for a multiple of reasons. From my understanding and as rumor has it, many, many of these stores are all run by one parent company.
Take a look at this example
here. Not sure how your eBay view is set up, but you may notice many different sellers offering the same item through multiple store names. These may be rugs which are on consignment... However, from my experience, and viewing many eBay rugs, the amount of carpets displayed by several dozen sellers in different inventories with different floor boards leads me to believe many of them are connected. I think one company may dole out rugs to certain "stores" depending on condition category, grade, etc: satellite stores for one company.
There are a lot of points to make here. My feeling is that many of these rugs can be categorized in several different ways: lower grade/coarser rugs, newly made "seconds goods", worn or previously owned pieces, carpets not "suitable" for american taste, high volume production, and general overstock.... Point is, if you have a heavy representation online, you can afford high turnover. The high majority of carpets on eBay are not what would be considered "generational" rugs. They're meant to be used, and often are not as durable as rugs which would be imported by regular wholesalers with specific quality controls. These are rugs which dealers purchase by the masses overseas, and may even spend more on importation than the cost of goods themselves. I think this rug you found would be considered a "seconds good" only because it appears longer on one end than the other, and sometimes the dyes may not be as colorfast as other carpets. They're hand knotted, but really meant to be used, enjoyed, then replaced. However, with low traffic, these can last for many, many years.
A lot of these rugs end up in antique shops around the country and may be sold for higher prices. These are "wholesale sellers" in some sense, however, some of the goods are just not what would be found in higher end "retail stores" They are some bargains to be found on eBay, but
you have to look out because there are some less obvious reasons why prices are so low.
Also, a lot stuff the cost of rugs into the shipping fees, and don't pay eBay's final value fees.