Hotel: Quality Inn & Suites Toronto Airport East
This hotel is conveniently just a few miles from the airport. It offers a free airport shuttle and free parking along with free wireless internet access through out the hotel. The front desk staff is very friendly and helpful with local information.
Like all hotels the rates fluctuate but for my stay I paid about US$ 58 per night booked through www.booking.com. This was much cheaper than the rate offered on the hotel website.
Car Rental: Payless
Rental facility is located off airport property and requires you to ride a tram to a pick up point. However, the van service to Payless was quick and the price of the rental was definitely worth it. Through www.orbitz.com I paid US$16 per day plus taxes and fees.
Total for two days, US$62.
At the Payless office they have free Wi-fi and there is a Subway and Pizza restaurant next door. Their location provides easy access to major highways and car rental return is simple.
One draw back, if you drive to Niagara Fall the quickest way is on the 403/QEW. Portions of this route is a toll road that is automatically billed from your rental license plate number. There are no manual toll booths so you will have to wait about a month for your credit card to be billed toll charges.
In Florida, many rental car companies offer you the option to pay a toll surcharge upfront and I do not know if this service is offered with other companies in Toronto.
However, I imagine the price and service from Payless is going to be tough to beat.