Superstores could sell a collection of produced products
There should be 2 superstores at RL 50,30,10
e.g. Fridge, Microwave, Glasses for RL50 called "kitchen Starter Kit"
e.g. Recorder, Guitar, Microphone for RL30 called "Band Starter Kit"
e.g. Wooden Table, Picture Frame, Wooden Chair for RL10 called "Furniture Starter Kit"
These would obviously have there own norm price and would generally sell less in a superstore and at a lower average price of all the goods in each collection
but it would be easier to keep shop value at 150 and you could produce more profitable goods in the superstore but sell less
thus making it an alternative but not an advantage in game play 
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OR have superstores so you can sell mass amounts of things in 1 store instead of having loads of single stores
the superstore would have sensible items that people would realistically buy in bulk like fuel and bread