Since the 8th house is, as was mentioned above, the house of 'other people's money' and 'shared resources' or as i often put it, 'the products of partnership', Jupiter in this house means that throughout the life there will be money coming from these sources, and not necessarily through your own paychecks.
And I know this is true because not only do I have Jupiter in Cancer but conjunct Venus smack dab in the middle of the 8th, and I have always worked hard and never have had money except what is necessary.
I was left a house by my mom, but if I sell it I have to share the profits with my daughters....not a problem for me unless...LOL...I actually want to relocate....1/2 of what my house is worth will not buy me another house.
I am a professional astrologer, but that profession is a fickle one, and unless you have a 'gimmick' or have incredible good luck (which I do not - the idea of a gimmick is revolting to me) astrology can provide a moderate income (at times, and at other times not so much, depending upon the amount of money people have for luxuries),
you will need income from another source.
Not complaining - I can give readings till I'm 90 and you can't say that about most professions!
Back to Jupiter in the 8th: it's really about the aspects to it, the situation in your SECOND house (personal income), and other considerations.
HOWEVER: there is another purpose for the 8th house....several in fact. The 8th house is the house of 'other peoples feelings, ideas, values.' When you have Jupiter in the 8th you can affect these things in others. You can use it to promote your own values, or you can use it to be of great help to others. This is the house of philanthropy....in this house philanthropy is not only a philosophy, it is a PRACTICE.
OR...you can be very greedy and unable to ever 'get' enough...enough love, money, things, power. Remember: the 8th house is Pluto's natural house. It contains a lot of potential personal power.
LIN