I wouldn't pay even $100 for the bike!
That particular model is the lowest end bike that Shogun made and could be bought new for $50; bikes like that at garage sales etc could be found for $25, in fact I bet he found it at swapmeet or a garage sale and paid $10 for it and cleaned it up. The rims are alloy because at some point in time (can't remember when) steel rims seized to be built due to their inability to stop when wet, so those alloy rims are only on there because the bike was built after that time and I can be sure they are of poor quality as would be the hubs. The ad says Shimano components but I can bet their the lowest grade components they ever made. From the pics, but can't tell for sure, the front derailleur appears to mad of chromed steel thus another tip off the components are of the lowest quality. The seat is also a low grade Walmart seat that in short order your going to replace due to it being uncomfortable. The handlebars have the old foam grips that no longer are being made, and since they are old will probably start to crumble when you use the bike and have black particles on your hands everyday.
The frame and the chrome handlebars, seatpost, and metal pedals are all a huge tip off that this bike is the lowest grade bike Shogun made, and also the bike would probably weigh around 30 to 35 pounds.
You would be better off going to Walmart and buy their new road bike for $200; at least it would be a lot lighter!
Sorry if I sound like I'm blowing your bubble, but you have to know your bikes before you buy a used one that looks good in pics. If your wanting to buy this bike for your kid then fine, but the seller is asking way too much for it. If you want something older and classic then I would look around and wait till you see an older Italian, English or Japanese bike that was a mid to higher end lightweight road bike. Those will go up in value whereas the Shogun will go down from what you would pay for it.