I have had this dilemma before as I run a manga blog (Non-Kinnikuman related) and I often need panel shots to put in my reviews. Sadly, the only way I can do this is by asking the original manga-ka himself for some scans or, more often than not, I'll buy another copy used on amazon marketplace or Rakuten auctions. If you go for the latter option, always pick up a copy that is "fair" or "good". These are cheaper and aside from spine wear and sunbleaching to the covers/spine, the pages themselves are almost always in very good condition.
What books specifically are you after? The regular Kinnikuman manga? If so, there are LOTS of convenience store comics for sale used in places like Book-off in japan for as little as ¥105. These convenience store comics are bulky and contain entire arcs at a time. Ideal for "digitizing" your collection!