Do you honestly believe you can buy quality for $189.00?
Take your time, be informed. The companies trying to peddle quality vinyl windows for less than $200 are simply using that advertisement as a ploy to get into your home and sell either a higher priced window or tack on the necessary options needed for a basic installation (ie, screen, foam sealed install, trim pack, debris removal, lead clean up, warranty, etc.)
As a veteran in the window industry, it is imparative for any homeowner to compare simple performance data such as DP ratings, U vales and warranty. Do your homework and ask questions. If anything, ask for One satisfied customer or an install from an actual customer who spent less than $200 for a window installation and see how happy they are with the purchase!