It might be a wise concept to forgo the $$ system entirely. If someone unlocks a gem they should be rewarded, not considered lucky because they drafted them.
In my league the format is, that which ever round that player is drafted in, if you wish to keep that player for the next season you lose the equivalant draft pick.
So if you want to keep Pujols, you lose your first round pick, but, if you say drafted Cole Hammels in the 18th round last year and want to pick him, then that it only costs you yor 18th round pick.
For multi-year keepers, the rule is going to be that your keepers draft slot increases by 2 rounds, with the highest round being the 3rd. So using the Hammels example again, in the 2006 draft I took him in the 18th, I forfeit my 2007 18th rounder, 2008 16th rounder, 2009 14th rounder etc...
We are only in year one of the league, so I cannot tell how well its going to work, however, its a sound and simple to understand system.
The system you have proposed seems a little difficult to grasp, as well as complicated to keep track of. A "more fair" system might be that instead of using the cash system, each year base the pick you lose on the CBS Sportsline ADP (average draft position) for that player on the day of the draft, they are fairly accurate due to the volume of leagues on the site.
Best of luck
Down 3, 8 straight.....The 2004 World Series Champions. The "Idiots". some gone, none forgotten.