According to FINRA's Trace system, RadioShack's 6.75% bonds due 2019 have traded as low as 12.375 cents on the dollar today. At those prices, the bonds would yield over 82% assuming that RadioShack did not default before maturity.
More details available in our full article on the subject, available here: http://commercialbankruptcyinvestor.com/articles/radioshack-6-75-bonds-due-2019-trading-in-low-teens-yielding-over-80
The stock isn't doing much better, surprise, surprise: