The Spot is a place in the Pavlov TTT map, OG Containers, near the terrorist spawn point. At The Spot you have a chance of finding 1 to 4 people standing there gripping their crotch. Go up to them and they will ask you "Do you want some. . . 'off the market items'?" say yes and one of them will offer you a selection of items, mainly a bomb, a knife, a flare gun, a phone, or a 50 Cal Sniper.
"Yooo, lets go get some bombs from The Spot!"