You'd have to treat it with caution. For one -- it appears to be a noname bike. Secondly -- what materials was it made of? Thirdly -- who in Costco will assemble and adjust the bike, and how will it be maintained by them on an ongoing basis?
When you take a $140 Costco bike, and add about $40 for a proper LBS tuneup, you are in the $200 range. This is within shouting distance of the entry level LBS bikes... you may even score a good second-hand bike for around that.
I know whereof I speak, owning both a Walmart Roadmaster Mt Fury and a better LBS bike. I still hang on to the Roadmaster because I can afford to take risks with it that I wouldn't with my real bike -- such as throwing it on a boat, using it in bad weather, etc.