According to "Midland Railway Carriages" (Vol. 2) by Lacy & Dow, a pair of Midland dining carriages of 1892, built for Anglo-Scottish joint stock to the same specifications as the Midland's own first dining carriage of a year earlier, cost between them £3,440 plus £210 for oil gas lighting (p. 437). That makes a total of £3,650 for both vehicles, or £1,825 each. These vehicles were 60ft long with a tare weight of 33 tons.
Edit: From the same volume at p. 445 - an 1898 renewal of Anglo-Scottish joint stock on the Midland entailed an order for 45 corridor composites at £1,572 each, 12 brake composites at £1,548 each, 12 third class carriages at £1,255 each, 10 passenger brake vans at £862 each, 3 dining carriages at £1,980 each, all being 50ft bogie corridor carriages, plus 31 six wheeled brake vans at £431 each.