Word for "without asking for it"
Solution 1:
Unsolicited is the closest single-word synonym I could think of; however, it has a drawback when applied to this scenario: it can have the connotation of unwanted. Upon analysis, without asking for it does not fit the intended meaning here either, as it carries the same drawback. The best option is to rephrase:
If you want people to start offering you jobs, buy this book.
If you want to start getting job offers without even applying [for them], buy this book.
Turn the tables on finding employment - get jobs to look for you!
Tired of searching for a job? Let the job find you! [courtesy @ajk]
Solution 2:
You could try snatch:
If you want to learn how to snatch a job offer, buy this book.
I was often told off as a child for snatching, because I should ask first.
Solution 3:
You could also try using headhunted.