Britney Spears is finally off the hook for the nearly $1million yearly child support payments she forks over to ex-husband Kevin Federline for their teen sons, Sean and Jayden. But RadarOnline.com can reveal her friends fear the pop princess will find another way to blow through her dwindling fortune. The 42-year-old Baby One More Time singer had been paying Kevin $40,000 a month for each son – or a staggering $960,000 annually – since Spears’ public meltdown in 2008, which led to Kevin being granted sole custody of their boys. Her payments for Sean ended when he turned 18 last year, and she’l…