The short answer is Yes, they are worth it. Especially for someone who doesn't really have that much experience.
They say the certs are worth about 3 years experience. I can say that having a cert vs not having a cert can help. If you have no degree and no experience, then a cert is probably the easiest or fastest way to get experience. Keep in mind too that if you're applying for a job and have taken (and passed) a few IT classes, you can mention some of that on your resume to show that you have some familiarity with that topic. Example would be the Security+ class I took. I haven't made it in to get that cert just yet but I took the class at school and it went over things like account management in Active Directory and end point security. I didn't have years experience, but if you asked me on day one to create a basic user account with certain privileges, I could have done it.
The certs are no longer good for a lifetime, but that isn't a bad thing either. The purpose of 3 year renewal is to make sure you're current on the information. If you had an A+ cert from 1999, you might not know a thing about tablets, cell phones or laser printers. As the IT world is changing, CompTIA is trying to add more information to include these technologies. The Cloud is growing in popularity but when I took my test 2 years ago, Cloud computing and mobile devices weren't on it. Now it's information you're expected to know.
Another nod to the certs is that you don't have to renew each one every 3 years, just the "top" one. I have my A+, and I'm working at getting my Security+ after I finish moving (Jan or Feb ish). When I get my Security+ cert, it will automatically renew my A+. In 3 years time, I will need to renew my Security+ which will again refresh the A+.
There are other ways as well with continuing education. I haven't done anything in this area yet so I'm not 100% on it, but you can catch classes or seminars which will yield so many credits. You'll need so many credits to renew your cert, but it means you won't have to go through the testing process again... and that can be annoying I'm sure.
I want to say my A+ cert was about 350$ but I could be wrong. Without much prior experience that a company might take seriously, the A+ I feel helped me get this job. I knew the basics and every company with have their own twists on stuff, but if you asked me to build a PC from the ground up, I could do it. I could troubleshoot most printer issues. I can deploy a new image to a conference room PC, set up the wireless phone system in the room, and hook it all up to the new projector. Could I have done that without the Cert? Oh course I could, but the cert let the company know that my resume wasn't just fluff. When it came time for an interview, I was able to show them my cert card and answer questions about how I would go about tackling issues that may arise.
I don't regret my cert and look forward to getting my Security+ soon.