Samuel and Michelle Kerr share caps and inventory. However, they will only sell certain item categories from that inventory. Samuel only sells aids, and Michelle also sells ammo but not alcohol. Neither sells misc items. Also, caps accumulated via Samuel repairing items are tabulated separately from Michelle's caps on hand.
"When 15 shut down, 95 became the route NCR citizens use to get to the Strip - or limp back home, after the Strip's drained 'em of caps. We get 'em coming and going. Coming, the suckers flush with caps they saved to gamble on the Strip... and going, the same folks, but now they're losers who'll trade you the shirt off their backs so they don't starve before they make it back home. Add in the troopers marching back and forth from McCarran and the Dam, and well, let's just say we don't miss Primm."