After giving my previous negative review of this product earlier, I think it's only fair to clear up some things that have been posted:
Yes, a wiring harness is going to be required. But that doesn't automatically mean $50.. $100.. $150 dollars. It could be as little as 5 bucks depending on the vehicle you'll be installing it in. Even the most expensive interface modules out there go for ~$80 online. And that's absolute worst case scenario. Most of your GM vehicles will require an interface of some kind. And Toyota's with the JBL system often require the TYTO-01 interface. If you don't fall into one of those categories, odds are your harness is very cheap. (Others left out due to a lack of offering in this sale, so it's irrelevant).
Next, an antenna adapter is not required for every vehicle. If it is required for yours, they can be had online for $5-$8 all day.
True, your factory steering wheel controls are not going to work without another add-on interface. Metra's is 50 bucks from Amazon and programs itself in 95% of vehicles. PAC electronics is another well-respected name and offers SWC interfaces for $30-$40 on Amazon. Not every vehicle even has steering wheel controls and, from my experience, people that do have them don't seem to care about them much. But others do. It's your call.
Just making it clear that the installation parts that are needed may end up costing many buyers under 10 bucks. Do your research about your specific vehicle before assuming it's going to cost an arm and a leg, as it won't for a majority of you.