There are at least two solutions for this kind fo situation:
Websites such as Betabound.
They collect and organize a wide variety of beta testing opportunities from all over the world and post them for free.
You can submit your project there for free.
Facebook groups for Beta testers
There are also companies that are ...
Some projects require crowdsourcing testing, while some outsourcing, I'd recommend you to use both of them! Some companies suggest software testing for free, like QAwerk in terms of their weekly bug crawls. I think that independent testing of your product would be an excellent experience for you!