One of the things we’ve explored with Three Trembling Cities is public non-festival screenings. So far, we’ve screened at the New York Public Library a couple of times, the Irondale Theater (as part of an evening on immigration/immigrant rights), a bookstore, and at a couple of college campuses. The event has to be a good “fit” for the series. Overall, I’ve spent less money on these than I do at a typical festival (especially when you factor in travel + food + lodging + drinking).
The flipside is that these events were for connecting with audiences and creating new fans, rather than networking with other creators and industry folks, or picking up good reviews. So we’ve also submitted to webseries-centric fests, and mostly avoided “film”-centered festivals because they often want a premiere.
If you’ve made a genre project, you should consider submitting to sci-fi/horror/fantasy/comic cons. The entry fees are usually pretty low compared to film festivals, and if you get in you typically get one or two day passes. The projection systems and screening rooms at many of these places isn’t the greatest, but you will never get a better, more engaged audience, and the organizers have always been really friendly. For my previous feature, I also picked up some great reviews and interviews, and even sold some DVDs! [I’ve also screened at sci-fi bookstores and sci-fi meetup groups].
If you’ve made something that’s not genre-specific but does have a niche audience, I would look at what public gatherings/events that audience engages in (including festivals, but also professional conventions, meetup groups, etc.)
Anyway, those are some ideas. Good luck!