Hi Kumar, as a beginner to GCP, I generally recommend *against* using the free trial when exploring the product group. (BTW, in English, there is a difference between "trial" and "trail".) As Joseph mentioned, there is an
"Always Free" tier (multiple GCP products). This daily/monthly free quota for participating products (1 free VM, 5GB disk storage [US region], 2M Cloud Functions calls, etc.) is always available to developers. As long as you stay under the quota, you will never be charged for their use.
I recommend you do NOT use the $300USD Free Trial because of 2 main reasons: 1) the trial lasts exactly 12 months from when you activate it (the clock starts ticking immediately) and 2) it is a 1-time offer (can't get it again). You only incur billing by exceeding the Always Free tier quotas, meaning you don't "eat into" the $300 until that happens. Do your due diligence, research which GCP tools to use, and only activate the Free Trial when your normal usage on GCP consistently exceeds the Always Free tier. Otherwise you're not taking full advantage of the offer.
Good luck!
--Wesley