Best way to get vault keys?

[Chicken Daddy]

what is the best strats for getting vault keys

[InolienKiki]

I've seen them in loads of different places. Trading post, locker room, sometimes you can dig them up, morning room, and I think the place I got them the most frequently was Spare Hall

[Forblaze]

Alright, I finally got the vault key and I traded running shoes of all things for it. I don't know if this matters, but I had placed the vault BEFORE going to to the trading post.

My inventory, if it matters, is
coupon book
secret garden key
coin purse
emerald bracelet
chronograph
moon pendant
master key
shovel
running shoes (traded)
metal detector
silver key
silver spoon