I have a largely successful thumb rule on sourcing materials.maheshvivid2003 wrote:
material contract details
1. Do a extensive survey on the prospective vendors.
2. Commit the expected quantity of the order to them.
3. Get them committed to a competetive price.
4. You will see that all the materials are of the same quality/ quantity at every supply & they are sent to your place over a "single phone call".
5. This also helps you maintain a credit with the suppliers for a few days, just in case you are not at site to make a immediate payment.