Cost of signage?

For those of you that have a business with some type of structural signage what was the cost? My building is on a side street but only a block away from the main street so I want to invest on a really great sign to catch attention. There is a 15 foot pole that is meant to have a sign on.

What type of sign was it?
Did the sign company put it up as well?
Did the sign company do the design?

I would appreciate any help you could give! I have to have a site survey done first.

Thanks