Ok, so, here's my idea. Have a second tab of investment opportunities. Have these be in some way connected to the first investments, and have the related investments interact with each other.
For instance, you have Lemonade Stands. You should have Lemon Farms. Buying Lemon Farms brings down the cost of opening more Lemonade Stands, and buying Lemonade stands increases the profits of the Lemonade stands. You could continue to add layers to the investments as well, and even have investments that effect multiple other investments. You could have Tree Farms that reduce the cost of Newspaper Stands, and Agricultural Sciences that improve the output of the Lemon Farms and the Tree Farms.
The possibilities are staggering.
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