1) The OED gives the meaning of dear-bought as ‘bought at a high price, obtained at great cost’, and quotes Chaucer’s use of it in <i>c.</i>1384.
It is actually a relatively common field-name, and Yorkshire examples date from the thirteenth century: 1240 ‘their culture called Dereboch’t', Kirkheaton
1622 Dearebought, Kilnsey
1847 Dear bought, Kettlewell. Different interpretations have been suggested Smith considered that the Kettlewell field had been so named because it was expensive whereas John Field thought the name was generally derogatory, a nickname for land regarded as a poor bargain
he quoted references in Cambridge, Cheshire, Gloucestershire, Lancashire and Norfolk. These are both possible interpretations, with meanings supported in general by early material in the OED, but the names were not met with in contexts which offered any insights into a more precise derivation. Since ‘Dearbought’ occurred frequently and over a long period, right across England, it was evidently in more common colloquial use than the few dictionary references imply. It is fortunate therefore that the parson of Melmerby used the term in his description of how peat was ‘won’ from moors in the North Pennines: 1677 as the saying is, they are dear bought for wee bring them two miles or more along & downe the craggie and steep mountaine in our trucke-carres to a place … whence when fully dried wee fetch them home in wheele-cartes. These were hard-won peats, and the emphasis is not on expense but the difficulty with which they were brought home and the time taken. In this context the meaning is more positive than the inferences made by Field and Smith, and it may be that ‘dear bought’ as a minor place-name emphasises time spent and hard labour rather than money unwisely laid out. The phrase 'as the saying is' clarifies the role that 'dear bought' once had in our everyday vocabulary.