How much does mileage matter when buying used?

Sorry to hear the sad news.

A "c' with 60k miles or less should be good to go. wont matter much
Pick the one you like better and that fits your budget and just look over the whole car.
Check the maintenance records etc.

ohh, and with the orange, hey maybe the color will be noticeable more!

 

More mileage (and more operating hours) means more wear and tear, of course—in engineering terms, the car’s parts are closer to reaching the ends of their designed service lives, and they are, statistically, more likely to fail. Without Toyota’s jealously-guarded reliability data and design information, however, it’s hard to say how much closer, or how much more likely, for any particular part.

You may wish to consider how much Toyota warranty coverage, if any, remains. As the Warranty & Maintenance Guide (PDF) for model year 2015 explains, the basic warranty expires after 36 months or 36,000 miles, whichever comes first, but the powertrain and hybrid system warranties are longer, and they transfer automatically to a new owner, subject to their terms and exclusions. The warranty is valuable not only because it might cover a needed repair, but also as a very rough guide to Toyota’s reliability assumptions.

Cars with higher mileage have also had more opportunity to have been damaged by lack of maintenance, or improper maintenance; as @dig4dirt kindly mentions, if the seller can provide records (or you can find them by registering on the Toyota Owners website, if the car was serviced at Toyota dealers), this may be less of a factor.