I had a friend die (we were in our 20s).
He was the pal who never had enough cash when we went out, who never bought anything when we went shopping, but we always took him along and bought him a coke or covered his share of dinner.
Well, when his dad went through his room he found a dollar stuffed in a sock, a five in a jeans pocket… final tally, a hundred and three dollars. Not as much as Becka’s dad, but for a broke kid, still shocking.
Not that I stashed myself, but I bought a car once, and picked up about $5 in change off the floor.
I then vacuumed the thing and pulled up the mats and found about $5 more.
I had to remove the seats for some repair and found another couple bucks. Spontaneous change generator.
But seriously, how did the previous owner lose so much change???
When I was 14, my allowance was a bill. I had no idea how the heck did I do it, but I was always short of money, but whatever, I’d always had less money than my classmates and I knew how to stretch it.
The next year as I reread my whole library again I kept finding folded bills among the pages. Oopsy!
But it’s not a good idea to keep a fifty for emergencies in the same clear plastic envelope where you keep your insurance & registration docs, and then hand the whole thing to a cop without thinking. Apparently.
I can’t think of any stories about money I have hidden, but I found someone else’s hidden cash. Last year, I bought a bag of sewing patterns at an estate sale, and when I got it home and later inspected the patterns to list for sale online, I found bank envelopes in two of them with a total of about $80 in crisp, fresh 1984 bills. 
Had I found the money at the sale, I would have turned it in to the company running the sale, but since I was already home when I found it, it was now mine.
My first job, in 1990 in Japan paid in cash, once a month. My ex-wife and I were living with her parents while we were saving some money, and I put the envelope somewhere and forgot it. When we moved out I found it, which was a really nice surprise.
Not me, but similar to Beckdawrek’s story, when my Mom passed away my Brother, Sis-in-law, and I went through her files–she had handled the money for the family all those years, and my Dad had no idea what she had in her drawer. When we looked she had literally dozens of envelopes with money in them for ‘this and that’, they totaled (IIRC) nearly $1,300.
I sometimes hide money deliberately, thinking that if it is out of sight, it is out of spending range. Sometime in the future, I will find it unexpectedly, and it will be a windfall.
Does anybody remember the fictional pirate who stashed money (and gold) around the upside-down house for his future widow (Mrs. Piggle-Wiggle) to find over time? He invented clever hiding places all around the house – drawers behind drawers, hollow chair legs, secret compartments. It was his intention that she be provided for, for a very long time after he was gone. If she ran short of cash, she poked around hidey-holes and found some more. Obviously pirate proceeds couldn’t be stored in the bank!
found brand new running shoes in my closet. I think they are about 5 years old
A few years ago, a parishioner at my church died, and a lot of her personal effects ended up getting donated to the church’s rummage sale. We ended up having to go through all of the donations very thoroughly, because she had hundreds of dollars stashed in her various belongings.
What did you do with the money?
Well, you didn’t have to: it would not have been in any way unjust for rummage sale customers to have benefited from found money in their purchases.
One time I found a $10 bill in the sleeve pocket of one of my coats that I had forgotten putting there. Came in handy because I was buying pizza when I found it.
Not really money, but…
2nd year of college, bought a bag of weed, it was pretty shitty. Next day, bought a much better bag, put shitbag away.
Come Christmas, everybody is gone, Athens GA is dry, people are selling pipes to scrape, it was crazy. 2 days after Santa I’m putting clothes away when I see a plasticky reflection deep in the drawer. Wasn’t a shit bag after all, it turned out to be the best damned weed I ever smoked. 
When I was cleaning out a trailer prior to demolition, I found something like $300 I’d put in a box. I don’t remember why. (I posted about this at the time.)
In middle school, I found a $20 bill in my gym pants pocket. To this day, I have no idea where it came from.
About a month ago, a man in Michigan had purchased an ottoman at a Habitat for Humanity thrift shop. After he started using it, he felt that the cushion was too lumpy, and unzipped the cushion and found $43,000 in cash in the cushion.
He returned it to Habitat for Humanity, who contacted the person that had donated the furniture. It had belonged to her deceased father-in-law, who must have hidey-holed the cash in the ottoman.
I found $200 cash in a side pocket of my backpack once. It took me awhile to remember how it got there but eventually I realized that it had been from a trip to China–we had taken a domestic airline flight from Xi’an to Shanghai and had been told by Chinese friends to spread valuables around and hide them well because the baggage handlers tended to rifle through people’s luggage and take small things. I guess I hid it well enough.
For a while, I would take whatever cash in my pocket, put it in my winter coat as I was putting it up for the season. It was never a lot of money, but it would always make for a pleasant surprise next winter… at least pleasant for a little while, as I would eventually remember I had put it there on purpose last spring. I stopped doing it after I was short on cash, remembered my winter coat and took it out early.
When my mother in law died, my father in law left everything as is on her side of the closet, drawers as is for about a year. One day he finally decided to box everything up to take to charity. When he was almost finished, he found fifty dollars in 5’s in a coat pocket. He then went back through everything in the boxes and ended up with around $2,000 in cash, that was just in the closet! He found several more hundred dollars in the drawers and more still in her books. I think it was close to $4k total.
Next holiday, he is telling us the story and my sister in law asked him if he checked behind the mirror on the dresser. He said no; they walk in there and find an envelope taped to the back with another several hundred dollars in it.
It’s been a few years, but he will still find money stashed around the house from time to time.
I used to find money all the time! In my parents’ closets…and their sock drawers, once under my brother’s mattress.
But then I got caught.