Buying a used road bike, need advice

So hopefully I posted under the right category, but basically I want to start riding a bike to University, around 6mile out, and my budget is 300-400, 400 is pushing it. I've looked into it and I see that the best option would be to get used one. However getting a used one is sorta scary as a first time buyer because I might get ripped or whatnot. I was hoping on some advice on what to get, either from Bike Direct, the local store here said they'd assemble it for 25 dollars, or one from craigslist. KHS Flight 500 Road Bike is the only one i see on craigslist fitting my price range really, but I don't know if that is worth the price. So any help would be nice. I'd prefer to buy one sooner rather than later as the bus stop is already 20min walk so I want to start commuting soon.

The one im looking at now actually is https://roanoke.craigslist.org/bik/5239477736.html
I have talked the price down to 375 but I wanted some opnions on whether that bike is worth it. Tried asking local bike shop for an opinion but for liability reasons they couldn't give me an answer on stuff they are not selling.