How much storage does Ubuntu use? I have Windows 10 right now which is using 17 Gigs. I want more storage space and I'm considering Ubuntu.
The answer is going to vary depending on the version (14.04, 16.04, 18.04, or 18.10 are the currently supported versions) and "flavor" -- Kubuntu will generally use slightly more than Lubuntu because it has more complex visual toys.
That said, you can make a very functional Ubuntu (even Kubuntu 14.04) install with 14.04 or 16.04 (this is from my experience) in 20 GB, including some limited storage space for documents and additional installed software. With a little care, you can trim the installation down a bit (though doing this after install requires having room to install and then getting some of it back) -- probably smaller than 16 GB if you replace larger tools with smaller ones (or start with Lubuntu, which uses the smaller tools by default).
There are other Linux versions that take up much less space than this; some of the ones that can run in 1 GB RAM or less can install in less than 8 GB of storage.
The nearest working example:
Lubuntu 18.04, 14.7 GiB SSD, 3.3/3.7 GiB /usr, 8.2 GiB are /home + free. Some office tools, GIMP, web browser etc.
You also can compress /usr to ≈800MiB (IDK how exactly, sorry) and sacrifice swap for more space (requires: 2Gb or bigger RAM, installing zram-config, increasing swappiness (it'll make system compress zram more often) and lowering cache-pressure (it'll prevent halting system because of overzealous cache purging)). UPD: also increase admin_reserve_kbytes to prevent system freezing on low-RAM.
If your small disk is actually an SSD, don't forget some anti-wear measures: New Lubuntu install - 2GB RAM, 32GB SSD