I have invested a chunk of my time and money to support 9(as of now) languages for the web UI, but as times goes on and new features and changes are being made, I sometimes have a need to add new text here or there. Usually nothing long, 2,3,4.. sentences. A word here and there.
It makes no sense to bother individual translators with such a miniscule job. Agencies are insanely expensive(from my experience 4x of a price of an individual translator) and so I have resorted to basic google translate, which is unfortunately stuck in 2010 and does not produce good results.
I have not found any "fiver" alternative for this situation, so I am wondering if people are doing anything differently?
You're not bothering them if you're paying for the job. On your part, all you need to do is to set up a web-based interface that makes it easy and fast for them to log in and add the translations.