Some disaster preps are best kept private. For example large stocks of food, fuel, blankets and other supplies are best not advertised lest one becomes a target for thieves, looters or official requistioning.

In a small town this takes more care since everyone knows everyone and is apt to remember those who purchased large volumes of supplies and perhaps to consider them as "hoarders" who should be "made to share"

In a big city, large volumes of supplies may be purchased for cash in any large supermarket not too near ones home. It is unlikely that the staff will take much notice, and even if they consider the transaction a bit odd, they know not your name or address and will probably never see you again.

In a small town, unusual transactions are apt to be remembered and use of cash rather than plastic cards does not help if everyone knows you.

Stocking up therefore needs to be done gradualy, or at a distant out of town store.
Mail order helps a bit for some goods.