On average, the cost of portable toilet rental for a day falls around $70 to $100. If you will need to keep the portable toilet on site for an extended period of time, the price comes down significantly to $85 to $398 per month depending on how often the toilet has to be cleaned and replenished with toiletries. It is crucial to decide just how many portable toilets to rent. If you have too many you, you might face wasting money. If you do not have enough portable toilets because you are trying to save cost, then people may end up waiting in lines and missing out on the work or fun they should be taking part in your event.