The best Baseball Card Collection Software available right now
appears to be "C2PRO 2.0" by LK2 Software.  The new 2.1 Beta is very
close to what you want.

Quoted from the 2.1 Beta Page of their website:

..."Track and Report card value statistics on any individual card and
your entire collection! Historical value tracking keeps you ahead of
the trend!

Just enter the price and C2PRO does the rest. Every time you change a
price C2PRO tracks the value change and over time you can see upward
or downward trends in your card's value.

Multiple Card Price Setting and Updating - Set and update multiple
card prices with C2PRO's Multiple Price Change feature.  Update high,
low, purchase and sale prices on all cards shown in the card gird.
Used in combination with the Quick Filters feature will allow you to
update prices on entire sets or collections in minutes..."

It appears they have an "Auto Update Wizard" where the company: LK2
updates with new card values frequently and as a licensed owner of
their software you simply use this feature as you do tpoupdate virus
definitions, only it updates the value of your baseball
cards/collection..."

Here is the link:
http://www.lk2.com/