Many of the materials that are required for a construction job sites are very specific. In fact, there are only a few suppliers of certain products that are required for job site safety. If you need a silt curtain, for example, then you will have to find a supplier that has the exact type of curtain you require. You will not be able to accept a substitute, especially if you have certain environmental impact requirements on the job.
To find a fair value on a silt curtain, be sure to speak with someone that you trust in the contracting world. They may have ordered a silt curtain in the past themselves. If this is the case, they will lead you to a supplier of these curtains and other related materials that will save you money and help you stay under budget.
For more information see this.