But I do not ever purchase materials when 1) the seller says, Only available if you purchase today, not available for you to purchase later; and 2) it costs a lot of money.  

We are in process of keeping materials kept up with and making binders now.

Not to mention having to buy the materials twice.... 

How much is the job and what portion is materials? 

Also, a suggestion for siding treatment and color:https://i.pinimg.com/736x/d1/65/06/d16506fe56a57f8f6a50276ce7303e2d--exterior-windows-exterior-colors.jpg Cross-gabled windows (visualize minus all the Tudor half-timbering):http://idolza.com/a/f/e/english-tudor-exterior-paint-colors-and-on-pinterest_tudor-style-windows_hobbit-house-designs-how-to-design-a-bedroom-small-bathrooms-mens-ideas-best-countertop-material-open-liv.jpg This could look outstanding, and bring it all together... look at the curved gable on the upper far right of this house.

He gave me tons of material to study and about 10-15 leads.

First, they dropped off my roof supplies (pallets of material) on 8/31.

Materials were all under $10 sqft

However, if you are buying down the rate with your own funds, you will definitely want to look at the break even point and consider a few external market factors. 

Materials and labor vary, depending on the area.