My first forays into the QwikLabs world were a bit daunting. Having completed 59 labs and a few quests, I feel much more confident both moving through the QwikLabs and tackling the free online GCP documents. By creating a QwikLabs account, you can preview all of the labs at no cost. Accessing the labs, however, usually involves some cost in the form of credits, but some are free.
Initially, I only worked through free labs. After I realized that it was almost impossible to complete a quest for free, I purchased just enough credits to complete the GCP Essentials quest. This quest made me realize that I wanted to work on the GCP platform. There are books and bootcamps and such, but a $55/month subscription allows unlimited access to the labs. I averaged about 2 labs a day which made the subscription cost effective for me. At the end of one month I canceled my subscription because I developed enough skills to begin working independently on GCP projects using the online documentation.
I should mention that @sathishvj on Medium maintains a page that tracks free codes for GCP training on QwikLabs. If you have a Twitter or Facebook account you can follow @QwikLabs to get the latest free codes directly. I found them to be a bit haphazard, but handy for exploring a wide range of topics.
Another way to get free access to the labs is to participate in periodic challenges that are also posted on Facebook and Twitter. Don’t be intimidated as there is no cost and you go at your own pace within the challenge timeframe. As I understand it, you can repeat the lab to improve your score.