Sumner Redstone’s latest embarrassment is having to unload his multimillion-dollar company that launched “Rock Band” video games for a paltry $49.99 — list price for “Rock Band 3” game.

Last month, investment group Columbus Nova announced it was buying Harmonix, which makes a Beatles version of “Rock Band,” from Redstone’s Viacom for an undisclosed sum. Yesterday, according to published reports, a person familiar with the deal said the price was about $50.

Viacom had told associates in December that it hoped to pocket a tax benefit for 2010 on the sale. Those familiar with the sale said the tax benefit was roughly $50 million based on the losses Viacom had rung up since it bought Harmonix for $175 million five years ago.

It’s the latest misstep for the 87-year-old mogul since last summer.

His longtime publicity executive dropped her harassment suit against Redstone for a reported $1 million, and he also gave 2,522 shares of Viacom stock to an attractive female, Rohnini Singh, and had his Showtime put her on payroll.