Usually , those SC free car wash , they just wash using normal cloth not those microfiber ones so tend to have swirl and scratches 
I only wash my car myself and not those roadside wash 

ok alwalys use microfiber cloth to wash , clean , dry and before u start washing , hose off the whole car then only start washing from top to bottom .
that's going to keep swirl to the minimum .
For the scratches , swirl , use polish to the affected area until the scratches is gone and add a layer of wax to protect it