Hi jfang the free trial has ended on render.com now.
I know some Brazilian users use heroku.com
Below are two links, one contains a few posts about heroku.com and the other is a currently working heroku.com deployment using fastai.
https://capydetector.herokuapp.com/
I believe you have to do some tweaking as you are only allowed a small amount of disk space. (this sometimes means making sure your model is small and you can fit the rest of your app in the small amount of disk space) provided.
Good luck mrfabulous1 