Tracking Value/Sales

By sales do you mean actual number of transactions or $ amount of those sales?

Tokens are the easiest way to do that. Keeping track of them can be handles simply by just keeping them in plain site for any other player to see...or you can use a player sheet (maybe designed like a bar graph and players fill in the bars to show their progress towards the goal.

Not sure how far into the design you are but....if you went with the latter you could build into the game some sort of bonus or extra action that can be taken once you reach a certain level. (I can explain further if need be)

I agree with the scoring tracks idea. But I'll give it a twist for your case.

It is what I call "multiple scoring tracks" with "VP trading mechanics".

Have several scoring tracks, each for the different bussinesses in the mall. When the player buys a bussiness, he gets the scoring track and scores in it according to his deeds.

The scoring tracks the player owns are his total scoring at any point, but they can be sold to and bought by another player. So you will take over and build up a retail brand, then you can sell it for a great profit to boost some new investments.

It's sounds weird, but it's pretty much like Monotony (sorry) Monopoly.

Keep thinking!