How did I get that (probably incorrect, knowing my math skills) estimate? Well, according to the NY Times, Leno's yearly salary is "probably more than $30 million" and The Jay Leno Show is "expected to cost less than $2 million a week." Assuming the show lasts a year, that's 46 weeks of shows at 5 shows per week, or 230 shows a year at a cost of about $530,000 per episode. Last night's show featured 6 segments: Monologue, unending car wash singing bit, Jerry Seinfeld interview, terminally unfunny Obama mock interview, Rihanna, Jay-Z, Kanye interview/performance, Headlines (aka Vagina Jokes I Found In The Paper). These bits obviously don't cost the same amount of money to produce, but assuming they did, each segment would cost NBC roughly $88,300.
I counted 16 jokes in that piece (and I'm being generous), which means that the utterly worthless tort/tart reform joke alone cost about $5,500, or one month's rent in a large NYC apartment in a super-desireable neighborhood.