Regarding $10/hour ... I don't know where you are or how much you value your own skills/time or whether you're just getting jobs to learn right now or what. But when I was at University (about 17 years ago) and did consulting work, I charged $30/hour. For me then, every gig involved some sort of travel from where I lived so I factored in wear&tear on my car and gas money and travel time to get that $30. Granted this wasn't perl but it involved some hardware and software work. Just a data point for you to consider.

Another thing, be sure when you are figuring your time to account for everything that eats your time so you don't accidentally cheat yourself. For instance, if you have a client that likes to talk on the phone, you may end up spending hours talking to them about their application. That's real time that you put your mind to their task. You should charge them for it as well as provide some communication time as part of your estimate.

Of course, it's also important to be up-front and honest with your clients. If you estimate 10 hours and it ends up taking about 8 hours to get half way through, you need to let them know that the full project is going to take longer than you estimated. Also, you might want to quote a range of time to give yourself some lee-way. Instead of saying "10 hours", maybe you tell them "10-15 hours".

Anyway ... just some of my thoughts.