I have Polk 5x7" 2-ways in my Ranger, and Pioneer 6" and 6x8" 3-ways in my car. I didn't even bother looking at the low price speakers; I started with the mid priced and then listened to the ones the stores had on display for clarity.
What I hate the most is a speaker that can't properly deliver all parts of the audio spectrum. I also don't have any subs in my vehicles, but those speakers do just fine by themselves.
Btw, for speaker testing purposes, I recommend listening to songs off of Pink Floyd's "The Dark Side of the Moon". Every song has those quiet and loud moments that can really sound different with different quality speakers.