For whatever reason the vault Overseer has thrown you out from the vault (he didnt even tell you why, can you believe the jerk?). Its also been deducted from surface surveillance info, that bottlecaps is the most used, if not the only, currency in the wasteland.
From the time you were standing alone, outside closed vaultdoors with nothing but your vault suit on and a bag of 100 caps, youve already managed to make it to a nearby settlement... congratulations!
Between all the let down junk shacks and the fancier looking, although also in poor condition, repurposed pre war houses you find a general goods shop and being the pragmatict vault dweller you are you go inside there first and think about what purchase is gona up your chances of survival.
What are you buying? (Budget 100 caps, no barter skills, you have nothing but your vaultsuit on, and i guess also shoes of some sort)