I got it secondhand from a refurbisher! I do NOT recommend buying a printer as your first-ever riso experience. my process was like this:
1. I paid a studio/press to print for me
2. broke even on the prints that I paid for (i.e. found that riso prints were not a money-losing venture)
3. took a workshop so that I could learn how to actually use a risograph. I also saw how much space was needed to keep a riso+ink drums, saw what other things I'd have to buy potentially: paper cutter, zine stapler, and lots and lots of paper. I learned so much about suitable riso printing paper over the past few months.
4. paid for studio membership so that I could use a riso myself instead of paying others
5. got sick of having to use a single-drum machine at the local studio and wasting so much paper on bad prints, so a friend and I decided to buy a two-drum machine
6. the first seller that I found scammed us and wasted about 1.5 months of our time. I got my money back through a credit card chargeback.
7. the second seller that I found was not a scam! I finally got my own riso printer about 11 months after making my first riso print.

it was pretty expensive, since we bought a nice machine and 9 ink drums. there are riso printers of varying quality and the cheap ones are super cheap, but also make worse prints and are hard to find ink drums for. I would really not recommend buying your own printer until you feel like you are actively earning money back from selling riso prints; otherwise, it's a huge loss of money, unless you are going to start a riso studio business and earn money by printing for clients or from letting other people pay to use your machine. Or, you could buy one if you happen to have thousands of dollars to spare, and you just want one for fun. if your riso printer ever breaks down in the future, it may be difficult to fix. this is a problem for future me..

if you just want the experience of using the printer yourself, if you're in a large city like NYC, LA, or Chicago, there are definitely riso studios in your area where you can take a workshop or pay for studio membership. I just didn't like dealing with the printers at the studio I was going to.

and if you just want to make riso prints, there are plenty of studios that you can pay to print prints for you. the ones I've printed with and whose quality I can vouch for are Lucky Risograph and Colour Code.

in conclusion, buying a riso printer is actually quite a risky move and I wouldn't recommend it to anyone else, but I knew what I was getting myself into and I thought it was worth it for Me Personally.