At 198,000+ miles the warning lights sent me to the dealer for diagnostic tests. Results came back as traction battery failure with a replacement cost of $3,200. Having previously bought some headrests when I bought my 2007 Prius used from AutoBeYours I thought I would check out their webpage and found that they will sell ($895) or install ($1095) refurbished traction batteries that they have built and tested. I went that route. I'll keep you posted on the results, but so far so good. The folks there are really nice, helpful and willing to show you around there operation. They also give a warranty for 6 months and proration for an additional 6 months, but check them out on the web for the actual details if needed. It was pretty quick too; less than 2 hours.
Steve at AutoBeYours is a great guy and among the most knowledgeable Prius mechanics in the country. JeffD