Honestly cheap stereo decks will sound cheap (most of the time) if you're already committed to the idea and already spending +-$150 on a deck you might as well get a good one. I really like Alpine, Pioneer and even sony makes a few good cheaper decks. (hopefully someone can chime in here on a good basic deck as I have most expericnce with double DIN
I had a Pioneer double din in my cobalt and I LOVED it, but those are more work to installl and waaayyy more expensive, but I did have GPS, bluetooth, movies TV etc.
Realistically just get something name brand, stay away from walmart and that for this type of thing lol. Go to a car audio shop where you can pick up everything.
But as for the install its pretty straight forward. At a car audio shop you'll buy an adapter mounting kit that'll fill in that empty space the singleDIN will make as well as mount the radio. They'll also sell the adapter cable as well wich has color coded wires
, just match them up to the wires coming from the aftermarket radio, again, they're color coded and labelled as to what they do. and connect them in the manner you like (I prefer solder/heatshrink) You'll also need to buy the Antenna adapter($10-15) which is just a plug and play adapter
This is actually a pretty good how-to with pics (I know its an '07 but its the exact same procedure) I followed this pretty close when I did my first stereo on my 2006 cobalt
I really wouldn't pay for something like this, especially if its just a simple single DIN system and you're good with your hands, its fairly simple and once the radio's out you'll see what I mean.
***if you have steering wheel controls you'll lose those unless you install some PAC system, I didn't bother as I didn't care enough, it was expensive and complicated the install. I dont know about the 2007+ but in the '06 I retained all my door chimes without having to do anything as the chimer is behind the gauge cluster.