It partly depends on how many are in your market; these vehicles are hard to find. I paid more than I had initially planned last month for my '07; I had been looking for 6 weeks, and my best bargaining chip was a Sand Dollar Pearl '07 with more miles that was nearly 4 hours away. I negotiated to a fair price, content with the condition of the vehicle (excellent), the color of my preference (white), and a very complete service history (vehicle sold as a CPO in 2012).
I wouldn't let lack of a timing belt service history keep me from buying a vehicle. Last year I bought an '05 Sequoia with 133k, fair shape, no timing belt done. I used the lack of maintenance as a bargaining chip, then negotiated with a few dealers on price to have it done to my satisfaction. At that point I knew it had been done right, it was one more step on having the car baselined, and it didn't need to be done for at least another 90k.