<$10k tC: Possible? Advisable?

You are making sound judgments there Jaffy. Yes, the Scion tC has maintained a remarkable resale value do to Scion Marketing, lower volume per year production, the popularity of the Brand/car, overall safety, and customer satisfaction (no run away gas pedals here). To find one under $10K would cause me to be a little cautious. Beyond the Carfox stuff, an independent mechanic's inspection should be done before you sign your name. Key aspects to check for is curbing as that seems to be the number one "driver error" issue out there.

Scion is a Brand angled towards the young, first time car buyer. These individuals tend to not have the driving skills yet have the bravado of a Formula One driver. The cars are very stout and can take a beating but sliding into a curb at any speed is going to cause some damage like the front k-member (sub-frame). This damage is explained here in this post, http://www.club-tc.com/forums/paint-body/4577-i-got-wreck.html#post24216. If you want to read more, you can use the Advance Search feature at the top of the Forum and search the word "k-member".

If it is manual, the clutch needs to be check out for excessive wear. There was a spat of clutches that had defective friction material. This only effected less than 0.5% of the cars out there. More likely the clutch may have been burnt by that of an overly zealous clutch footer looking to smoke the tires.

If you were to use a Dealership, they should know enough about Scions now. In the first few years, the Dealerships knew little to nothing about it; treating them as 100% Toyota. Well, Scions have some differences than Toyotas. One was window jamb protection. My 2007 Camry does not have this and only auto down on the driver's window. My tC has full auto up/down with jamb protection. These guys had to have this pointed out to them in the owner's manual. It is much better today so a Toyota Dealership might be best unless you have a mechanic that you trust.