HARO (Help a Reporter Out) is a bit played out at this point, but that doesn't change that fact it it's free, and accessible.
Everyday, you are sent 2-3 emails with a digested list of real reports with real inquiries. They're sorted into categories, and each one asks for a specific type of person to answer a specific question.
Now, that can work if you are that specific person answering a specific question. But, what are the chances of that? And when has following the rules ever got you what you wanted?
My advice to using HARO is this:
-Use a company email address. It's not necessary, but you'll come off as "credible" with a company email address.
-Respond quickly. If the email is in your inbox for more than 15 or 20 minutes, the reporter has likely already received the answer he or she was looking for.
-Keep it short. A few sentences is all you need. Anything more will probably hurt your chances (unless they advise you to write x amount of paragraphs, which happens from time to time).
HARO is by no means a guarantee, and it is definitely more saturated now that it was a few years ago. But free press is still free press. You can be quoted in major publications such as the WSJ, NY Times, etc if you play your cards right and luck is on your side.