I am the only person in the world still using DOS, and my spreadsheets are DOS spreadsheets. To be sure, there is Gnumeric and Open Office under Hacky Linux, and I use Excel at work, but for home finances, dieting, and stuff like that I use AsEasyAs, which is a shareware clone of Lotus 1-2-3. "As Easy As 1-2-3" get it?
I also have a DOS implementation of VisiCalc, which was the very first spreadsheet ever and only 15Kb, but it is simply too primitive to use. I don't like how you can't see where you're at with a bit-inverted cell at the cursor location like with AsEasyAs, and there's no help menu built in. You need to use a card provided by Apple for the commands. I keep it as a museum piece.
In the same way that VisiCalc was the "killer app" that sold a lot of Apple IIe's back around 1979-80, Lotus 1-2-3 was the killer app that sold the IBM-PC in the 1981-83 time frame. AsEasyAs actually improved on Lotus by introducing drop-down menus, and it was one-tenth of the cost. Now, of course, it is "abandonware" and is free, and why the hell not? The MS-DOS era is long over. But I'm Taoist. I turn back to examine closely what the crowd has passed by.
In the same way I boot Hacky Linux from a Live CD that incrementally improves, I boot DOS from a floppy disk that also incrementally improves as I trim unneeded utilities and add new ones. AsEasyAs is included in my boot floppy, as well as the latest copy of my budget spreadsheet. About once a week I remaster my FreeDOS boot floppy by using the command diskcopy a: a:. This allows me to recover from any mistakes as I change my config.sys and autoexec.bat. I have a phobia of actually installing an OS to a hard drive and relying on it to always work, whether it is Linux or DOS. To me, a hard drive is only used for storing content, not the operating system.