Help! Want to replace electric windows & tailgate for '88 Suburban- where to buy ???

[OverRunWithSons]

I am asking this for my husband........the only place he can find these parts is the LMC parts magazine, we want to replace the Electric tailgate window to a winder, and all 4 electric door windows on our '88 Chevy Suburban to simple no hassle Winders. ......
Here is what we need to start......Left & right glass channels for Tailgate, Window sash for tailgate, window regulator (manual) , tailgate handle assembly and whatever it entils to change from electric to winders for the 4 doors- he didn't get that far yet, just changing the tailgate parts buying from LMC is almost $400 ! Anybody got advice to a cheaper place to buy all this stuff ?? And how complex of a job this is to change would be helpful also. Whoever invented those crappy electric windows should be shot! And how this message board is used for finding parts, buying parts , etc. When we get this changed, we will be selling those motors, etc that we are taking out. Thank you!