Pay who to post where?  Your post showed up here, so if you are not paying anything, then the answer would be no.  If you mean to post an activity to the Strava app, then it is also no.  You can use the free service to post your activities, but you just won’t have as many tools and features as those who do pay. 

So i do not have to subscribe to strava to poston strava? Asking because before strava had this 30 day trial I couldn't post. But then when the trial started, I could publish posts on strava app. 

I mean this.