The best free alternative to Poedit is Weblate, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to Poedit and many of them is free so hopefully you can find a suitable replacement. Other interesting free alternatives to Poedit are POEditor (Freemium), Pootle (Free, Open Source), Lokalize (Free, Open Source) and Virtaal (Free, Open Source).
Xliffie is designed for developers in mind, with functions like checking printf-formatted string (make sure your %@ is not a %d in the translated string), search with regex, Google / Bing translated, etc.
Crowdl.io is a free translations manager with crowd translations features. Create a project, load your strings, and share your project's link with your translators. It can export to different formats, like JSON, Android and iOS.