Thanks Don, wish I wasn't leaving so soon, wait, I take that back. Wish I was there....
Of course it varies with which computer & which battery. My Oceanic Versa Pro is so old that I had to replace the boot last year - cracked and falling apart. Fortunately google found me a good buy on one. It was challenging to get the computer in for some reason, my memory is foggy, but my home dive bud sells & repairs vacuum and sewing machines - any brand, any generation, so it didn't take him long. I have him do my computer battery changes as well.
But the CR2450 is common among computers and many other electronics, even my first CO analyzer, so Radio Shack carries them. I remember how insulted I felt to pay $5 or $10 for one just days before a trip when I noticed I was short.
And still, prices vary a lot over time, and I guess they are up for now...
Here is a package of 2 for $1.16, free shipping:
2X 3V CR2450 2450 DL2450 ECR2450 5029LC CR 2450 Lithium Button Cell Coin Battery | eBay
Or 5 for $1.96:
5 x CR2450 2450 DL2450 ECR2450 5029LC Button Battery | eBay
But if you're leaving in a week, there are US sellers...
Here is 1 for $1.36
CR2450 Lithium Cell Battery DL2450 2450 Made in Japan Great Free USA Shipping | eBay
Or 2 for $1.95:
2 PC New CR2450 CR 2450 3V Lithium Battery TC | eBay
So whichever model you need, look there, shopping
New only, and
US sellers if you're in a hurry.
As you said, Lithium batteries have a shelf life of years so even if it's old stock and/or unknown brand, doesn't matter. It's quite different for cell phones & rechargeable batteries, which I have shopped a lot for my family and my dive bud's. For those, I make sure to shop
New OEM for your make & model as there are sellers who will send tested, used batteries if you are not careful, and off brands that can even be dangerous. NiMH batteries for cordless phones and cameras are different still, but I am rambling... :blush: