Should I buy windows myself or go through a company??

[Alec Jacobs]

I am in the middle of renovating my first long term rental and I need new windows for the upstairs unit (it is a top bottom duplex). I got a quote from a window company and it was going to cost me around $11k to replace 8 windows which is around $1.4k a window for a mid grade replacement. The windows I am looking for is something in the middle of really cheap and super expensive because it is a rental however I plan on holding onto the property for a long time. 

Would it be better for me to go with cheap windows or is it possible for me to buy windows myself and have somebody install them and just cut out the middle man? Any advice would be greatly appreciated. Thank you!