Sane, with your target prices, it shouldn't be difficult to find a wide variety of items to meet your needs. J Crew, Gap, Banana Republic, Lands End, Brooks, etc. will all have decent chinos and business casual shirts. Focus on fit. Stay away from excessively baggy or tight items.
You might actually want to ask this same question over in Streetwear & Denim for less mainstream suggestions which would be professional but offer a bit more character.