Please tell us more:Is this wall in a basement or above grade?

If the house is slab on grade, you'll have a bigger problem, and if you aren't all that experienced with these types of repairs, it's probably better to not make this deal. 

Say your houses is a slab on grade single story house with a finished floor elevation of 105'.

Not surprising when you think about labor costs vs rental grade material costs.

Alternately, if you have something solid behind it like a stud behind the drywall, you could predrill a couple holes and use a cabinet screw (exterior grade, we use GRK from Home Depot) to gently pull it back against the wall.

If they're older aluminum/contractor grade they probably aren't very energy efficient.  

My site just takes basic bullet points of a deal and classifies them in grades.  

On grade parking.THANK YOU for reading this and any feedback is appreciate.

I have a hard enough time getting people to upgrade to real windows over the low price point builders grade I use.

Scale is usually achieved at 75 doors or more in size.