Was it an original or a copy?
Expensive for a copy that can be had for about £25, 'cheap' for an original.
I have one and have been offered a 3 figure sum for it. One sold last year? in the USA for about $850 if I remember correctly.That's about the going rate as these are very rare and good reading I might add with some excellent pics of 'as it was',
old adverts for reference and a pullout at the rear for the BSA air rifle.
I am probably wrong but it may well have been the first dedicated book for airgunners which makes it rather desirable to a collector.
Just to put it in perspective, the original selling price was 1/- in old money. There were 20 to the £, so 5p would do it!

Carl