They'll also come with a bag rather than a hard case, though this isn't a big deal to many people. So you got exactly what you paid for. If you bought those same model number tools at a different place you would have got the exact same tools. If you want nicer tools you have to pay more for them. You know, regular market-driven purchasing. EDIT: this isn't to say that your tools are bad.
Even the cheapest DeWalt stuff might very well be worth the money you paid for it. I'll let you as the consumer make that decision. I just wanted to clarify that just because you bought it at Home Depot doesn't mean you got a surreptitiously inferior tool.
This is correct. If you are comparison shopping you compare model number to model number. Home Depot will often carry combo kits that include cheaper versions of similar tools. If you check the model number on the ones in the kit, it will often be different then the ones sold individually. Many manufacturers will make tools for specific price points.
Replace some metal parts with plastic, include the cheaper batteries and they can get the price down. What they don't do is stamp the one with more plastic parts with the same model number as the more expensive version. Sometimes Home Depot will indeed be selling the exact same tool for less. Sometimes the manufacturer drops the price to make a big sale to a chain, sometimes it's a combination of sale pricing/loss leader planning by the retailer, sometimes both. For example, HD might tell Dewalt - Hey, your combos are selling well, we'd like to feature them as one of our black friday sale items. If you can give us the combo for $180 wholesale on 1 million units, we'll price them at $200, and move them all within a month, then come back for more at the regular wholesale price. Even if the regular wholesale price is $240, Dewalt might go for it just to drive sales, even if there's no profit, and might even take a loss if they can justify it for inventory reduction or advertising.