Always price your washer fluid of choice before buying a washer.
And as has been posted, know how much you will need.
Know that the fluid evaporates slowly but surely.
The fluid will cost more than the unit on most.
Factor in odor. Odorless fluid stinks, the other suggestions smell worse.
Remember safety. A fire from a poorly chosen fluid is no fun, in fact it may kill you or your loved ones.
If you use non-standard fluids, assume your insurance company will desert you in an accident.
Keeping it in a small out building or shed makes you and your wife happier.
Going with the water based ones is much safer, cleaner, but won't clean as well.
On the ones with the big barrel below, there are tricks to let you use less fluid than the minimum required.
Best, is partially fill it with glass jars, or other solvent impervious bulk so you need less fluid.
I recently cut the top ten inches off my solvent barrel to avoid having to put 12 gallons in it. Now it works fine with 6.
All metal solvent tank will last virtually forever. I gave one to a buddy ten years ago after ten years use. Still works fine. That was a very cheap import.
I use a 25 or more year old US made.
Pumps wear out. Or don't. My pump was made in the 80's, but the small washer next to my big washer the pump only lasted about two years.
Pumps cost almost as much as washers.