If the item was sold with a separate shipping price, the shipping will not show as part of the price when you compare Sold listings.
If the item was sold as Free Shipping, the seller included her shipping costs in the price.
So you may see an item sold as $10 or as $15 when the buyers both paid $15, since only the second one has the shipping included.
If you see a big disparity in selling prices, it is worthwhile making the extra step and actually looking at the listings, particularly at the Shipping tab.
And many sellers include all or part of their shipping costs in their asking price, because buyers hate to pay shipping, no matter how accurate.
Which would you prefer to buy?
A $5 item with $10 shipping?
A $10 item with $5 shipping?
A $15 item with Free Shipping?
A $1.00 item with $14 Shipping?
The last one still occasionally shows up when stupid sellers think they will pay lower eBay fees. However, eBay has charged fees on the shipping cost for several years now.
You don't want to deal with that guy, because he has shown you that he is not as smart as he thinks he is and will be difficult to deal with.