Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
dear (adv., adj.), dearly (adv.)
When they mean “at a high price or cost,” these two are interchangeable adverbs: These strawberries are priced too dear [dearly] for me; in all other contexts, only dearly is an adverb: I’d dearly love to be present when they meet. Dear is also an adjective meaning “expensive”: Medical insurance is becoming too dear for many Americans. The sense is more frequent among the British; more commonly Americans use expensive or costly, favoring dear instead in the sense “beloved, treasured,” as in my dear friend. All these uses are Standard, however.
