I think you would be able to find this one for $90 or so. $150 seems excessive.
1st prints can be found for $20-30 on ebay. a 2nd print shouldn't run more than $10-15
Yeah, they shouldn't be, but it's one of the books that is never in over-abundance on ebay. Even when the first print was only a cover price book, I always sold second prints for $25 with no prob because my copies were the only ones out there.
If people want them, they pay. The first print is plentiful. The blue cover, second print, not so much.
With that being said, you can still get them for $30 on ebay. The last copy I sold, I moved for about $65.