My main sim (before I moved him to a fresh-new Sunset Valley, now with LN lots) owned all the properties and buyable community lots. When it was needed, I ranked stuff up to 3 stars, so in the end he owned the entire neighborhood and it was all 3-star-fancy, giving max profit. It took around 22 sim-day hours to completely collect the profit from all of the lots. Every week I would get around 1.4 million, something near that. Obviously, I just let the cash grow and grow, and collect once every sim-month, so that those 22 hours are worth it.