Show HN: What do you think about this page? I am a newbie to web design.

I don't think you can put a price on it. The price is dictated more by the context than the resulting mockup.

In one context someone might have paid a few thousand for this design. In another, a few hundred. It is valuable as a solution to a problem, so asking how much it is 'worth' is like asking the value of a chess move. Again, it's all about the context.

What I can say is that I know of designers charging AU$50/h for work of a seemingly similar quality.

Good job. I can imagine giving you a web-design job. I have no idea what this would be worth though. I wouldn't be paying much more than $300 if I was a start-up. If you want to check how much this could be worth - ask that on upwork for example. Post a job and wait for the reply from the random set of UI designers, ask for quote and check their portfolio to get an idea how good and expensive they are.