Even the most inexpensive drum machines still tend to be not-so-trivial purchases, but you may have an easier time rationalizing this one. Rhythmo has started a crowdfunding campaign for the Beatbox, a build-it-yourself MIDI drum machine kit aimed at making beat production more affordable. It's not exactly your typical drum machine between the cardboard body, Japanese arcade buttons (for both drum pads and function controls), four knobs and a gamepad-style analog navigation stick, but it'll also be available to the earliest backers for $99, or $150 at retail. That promises to be a serious bargain, even if it'll take you roughly an hour to build.
You might not need extra gear depending on your artistic inclinations. It includes two 50W speakers to pump out music all on its own, and a 3,000mAh battery will keep it running when you're nowhere near a wall outlet. This isn't a completely stand-alone instrument, to be clear -- you'll want to use either a digital audio workstation (it's compatible with apps like Ableton and GarageBand) or Rhythmo's own smartphone app to complete your music production workflow.
It shouldn't take long to get one in your hands, at least. Provided all goes well with crowdfunding, you could get a unit as early as spring 2020. It might come just in time to help you soundtrack a few summer parties, or to help teach kids the ins and outs of electronic music making. And those are really the goals -- this is an entry point and educational tool for people who have little to no experience with creating music.