a pack of dry ice? how about one of those cheap styrafoam throw away coolers, put the dry ice in it and put the gift card on top or tape it to the top of the cooler? Just a quick thought...

You could freeze the money inside a plastic container - as long as they don't hack at it, but just let it thaw the money would not be damaged.
Would be fun to see their faces when presented with a frozen block of money...
Suzan J

You could look for a dollhouse freezer or refrigerator and put the money in that

Hi, I spend most my time at the garden junk forum but I thought I'd join youall for a bit.
I'm thinking of you making something like a shoe box look like a freezer. Cover it with white tissue or paint white. Add hinges and a handle and maybe a logo of a well known brand. Then you could put inside a paper with their favorite decadent frozenitem. If it was my dh for example I would print out a piece of card stock on my printer on which I had printed all ice cream containers and then glue it toward the top of the box as if the freezer was full of that item. And lay the gift cert or cash on top.
have fun
kathy

Take a plain white styofoam cooler & paint it to look like a freezer, hinges at back & handle at front could have a name like "Freezeworth" down in lower corner then inside have the thing filled with "frozen foods" carefully open frozen veggies & save containers & refill with styrofoam packing s's. Meat could be thin piece of styrofoam, like what comes on top of new DVD player, about 1/2in thick & paint it pinkish red & place in cleaned meat tray & cover with plastic wrap. Fill it full enough so they wonder what is going on & have pic of freezer & the money under it in a packet(Hey, I figured out this much you get to figure out the packet!!!) Have fun with your freezer or whatever you do! SEafood, meats, BBQ ribs etc come in mail in the type of cheap styrofoam containers & dry ice is always about gone by time you get it. Would make great "freezer" I carry 1 in trunk of car. Can't really hinge it as have to top off all around ,just fake them! Jan