You are right, there is no sign for a $4 weekday car wash and $7 weekend for a basic wash, those prices should have a sign, so people don't make mistakes bringing the car thinking on a price and paying for a different one.
The large signs on Manassas Dr and 28 both say $4 wash. I didn't see any additional banners, whch may be on the front (hard to see coming from Manassas Dr side).
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