Retaining wall estimate

[meets1]

Looking at a base wall. 100ft long, 3 ft in hieght. Bordering a building's property line. I did a search but prices are all over the place. Per sq ft, other says per hour worked, other based upon availability of job etc.

This is easy. Everything is within a 150ft of work area.

Thanks

[meets1]

Forgot to mention - NW IOWA location! Different prices for different areas of our world!

[treedoc1]

$10,500 for my area