Where are you located? If here in LA, I could tell you where to go.
When I was doing my house I bought my scaffolding...about 27 sections. I had it up for almost 2 years. The 2x12 planks were free (trash from a shipping container).
I paid about $900 for all the sections and then sold it for $600....and kept 2 sections.
Just so you know, standard 2x12 planks are not OSHA approved.