We also use PlanOn.  Everything else we saw required sheet-feeding.  Our main need is to copy from old bound books and plats that cannot be photocopied.  The PlanOn is a 'rolling' scanner pen, which can be bought for black and white or color.  It requires a learning curve to be able to get a decent image, but we are pleased.  It also in many instances can scan a computer screen, if you can't print what's on the computer.  Top-of-the-line with all attachments and software, including PaperPort, was around $300 several years ago.   It has saved us a lot of money in copy costs.  We scan index pages "free" just for our file, to be able to show the state of the index on that given day, since in some counties corrections are made and documents show up later that weren't there when we searched.   PlanOn is easy to find with Google, and very helpful.