Quite complicated though, perfect if Saving for rooms, food and furniture.
1. So however rooms you have, check a guest into all of them. So one guest in every rooom.
2. Look at the check out date.
3. Move your date on system settings to a day or two further from the check out date, so if one guest checked out on Monday and someone on Wednesday, my date should be on Thursday or friday.
4. Now get back on Sims 2. You will receive telephone calls. The more rooms the more cash!
Oh and repeat this for more cash!
I done this 3 times and got 3 rooms!