I'm skeptical of most free contests, honestly. Too many feel like data collection or anthology-mill schemes, where you 'win' a spot in a pricey collection you have to buy. But I found one exception last year: 'The First Chapters Prize' from The London Library. No fee, open internationally, decent prize money and mentoring. I entered on a whim, didn't win, but the feedback was genuinely thoughtful—more than I got from some paid submissions. The key is vetting: if it's run by a legit literary journal, university creative writing department, or a major publisher's imprint, it's usually okay. Random websites promising 'exposure'? Run.
WordHunt (formerly Scribophile's) quarterly contests are another solid free option. You need to critique others' work to earn karma points to enter, which keeps the community serious. The prizes are small but real, and the feedback you get during the process is the real value. Helped me tighten a short story that later got published elsewhere. I'd take that over a hundred no-feedback rejections from random places.