Exactly.
My current cat is a very industrious digger.
So was her predecessor. I actually tried sifting liners with him, and he promptly shredded them as well as the solid layer at the bottom of the stack.
Haven’t bothered to try them with Princess Razorfang Scissorpaws. 
Dollar bills? Roll them up and stuff inside an extra-large bottle of medication (think Sam’s Club size) … try not to do pain meds (like Tylenol or something), but something vaguely embarrassing that no one will go into.
Put it in a doggie poop bag and stick it outside the door with the pile of doggie poop bags.
Sew it into your coat’s lining.
With many cars, it’s trivially easy to undo a couple bolts or screws and take off a side of it or a quarter panel or some interior piece. Do that, then hide it in there in a bag or something. Bonus! You get to feel like a old-timey robber baron.
See post #30. Fanny pack indeed. 
Note for our British friends: Our “fanny” is not the same as your fanny, but that would work too.
I used to keep a couple hundred in emergency cash in a DVD case. I figure a robber isn’t going to have time to search everything.
Except by an Australian or a Kiwi who is too long between marmite fixes
I can carry at least ten bills without any trouble. After twenty minutes of movement, I can’t feel it anymore. I like tens and twenties, because there’s no place on earth that no one accepts a twenty dollar bill, while larger denominations can be harder to use even here in the states. Again, make sure to stash them in a Ziploc baggie to keep the sweat out.
The battery compartment of your vibrator. 
That’s why I specified Vegemite. I actually love Marmite (well, Sanitarium Marmite).
Probably too late for you since your already on your way, but I would purchase several old 8 track tapes, disassemble them throw away insides, keeping a small strip of the 8 track tape, glue to the slot opening before inserting cash and keep it out in plain sight.
Without the 8 track player of course … use “Age of Aquarius” no one would want to hear that one again 
Ah, but then I would have to find 8-track tapes. Can’t recall the last time I’ve seen those for sale.
I have no Marmite, but I do have a jar of Vegemite. Is that close enough?
-Order a Beer Belly from Amazon.
-Fill it with money instead of beer.
-Tell everyone you’re due any day now.
Try a thrift store.
You can also hide it in my rectum.
Get a clear glass jar and put your money in that.
Get a clear plastic bag and put your money in that.
Tape it to the bottom of a clear glass coffee table.
Get some fly paper and stick your money to it.