Trying to keep within $5.

Photo copy an instruction Card with S.T.O.P. and other survival info particular to the area including simple map, emergency numbers, maybe simple first aid (lay person's ABC's)
Leave room for notes, messages.

Heavy duty large trash bag for raincoat or bivy. More durable and
wearable than a cheap space blanket. Can get them in orange or
bright blue or red.

Whistle $1.40
http://www.dealextreme.com/p/outdoor-sur...or-93150?item=1

Fauxton light (Check to make sure they function) $.50
https://www.dealextreme.com/p/black-flashlight-keychain-22000mcd-10-pack-1253

Compass (Check to make sure they function)$.46
http://www.dealextreme.com/p/mini-compass-cube-5-pack-3295

Small Bottle of Gator-aide.

Short pencil with duct tape around it.


If they are adults, you could add

a lockback knife $!.99
http://www.smkw.com/webapp/eCommerce/products/locking+knives/Maxam%C2%AE+Money+Clip+Knife+-+Assorted+Color+%28Our+Choice+Only%29/MAX94530.html

or

a firesteel $.99
http://firesteel.com/firesteel-miniature