Me and Bobby McGee is strictly a three chorder: In G, it's G, D7, C (maybe with an occasional G7)

(G)Busted flat in Baton Rouge, waitin' for a train,
Feelin' 'bout as faded as my (D7) jeans,
Bobby thumbed a diesel down, just before it rained,
Rode us all the way to New Or(G)leans.
I pulled my old harpoon out of my dirty red bandanna,
I was blowin' sad while (G7)Bobby sang the (C)blues.
With the windshield wiper slappin' time, and (G)Bobby clappin' hands we fin'ly
(D7)Sang up every song that driver (G)knew.(G7)
(C)Freedom's just another word for (G)nothin' left to lose,
(D7)Nothin' ain't worth nothin' 'less it's (G)free.(G7) (C)Feelin' good was easy back when (G) Bobby sang the blues,
And (D7)feelin' good was good enough for me--
Good enough for me and Bobby Mc(G)Gee.

It's just the I, V7, I, I7,IV, and back to I, in whatever key you're in. --seed