Tier discount.
If I would get a whole-sim tier + 10% group bonus, I can fit 55 plots with 300 prims each on it. (15,000 prims per sim, 10% bonus land = 16,500 prims / 300 prims per plot = 55 plots)
This would cost me US$195 / month, which breaks down to US$3.55 per plot per month, or at a exchange rate of 250 (US$4/1000) L$888 / Month, or L$205 per week.
Profit per plot (when everything is fully rented out, optimistic

): L$300 - L$205 = L$95
Profit per whole sim rented out like this: L$5225 per week = L$22642 / month
Now ofcourse it will get a lot better if people don't actually use all their prims alotted, so you can probably "overbook" by as much as 50 - 100%.
Very optimistically again going with 100%: 110 plots @ L$102 / week
Profit in this case per plot: L$300 - L$102 = L$198
Profit per whole sim rented out like this: L$21780 per week = L$94380 / month
With the automated rental tools available and not too much hassle to find clients, it might be just worth it.
BTW: L$300 per week is not L$1200/Month, it's L$1300/Month (there are 52 weeks in a year or 13 weeks in 3 months)
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