My PM also knows local contractors and specialists, so when something does come up, he has more bargaining power than I would, and is able to recommend reputable suppliers.

Mother Nature, permitting, contractors, suppliers.  

House some larger storage tanks for waste that you could have pumped.3) Find a business (excavator, plumbing, granite supplier) and trade on-site "night security" in exchange for a spot to park and use of the bathroom/shower inside the facility.

I could not find a stone supplier that would do a job under $1000 because of the fixed costs of measurements, cutting the sink, and installation.

During this Covid-19 debacle I was able to make a deal with my Chinese suppliers (I run a small Amazon seller's business utilizing my contacts from over a decade in Asia) to get a good price on surgical masks.

Hains criss cross, reallist, real quest are example of suppliers.

They are checking with some of their suppliers to see if they are able to reduce or donate material. 

I have done both local cabinet suppliers and RTA cabinets from the Internet.

I then switched to a wholesale mortgage supplier and got another appraiser.

We were buying from Clayton's same supplier for a while.