The pros to no-charge are that you're offering self-protection techniques to ANY who may desire to learn it. That itself is a great service to the community.
The way I see it, is that you can't know if you're committed to something without trying it. I doubt you're going to meet someone committed to you and your teaching without having first met and trained at least a little with you. What I'm saying here is, regardless to whether or not you charge your students, you're going to find those who fall away from you, and those who stick with you.
What no-charge also makes easier is a second chance for students who didn't stick with it. Maybe a couple months down the road they want to give it another shot? It's not like they have to pay, so why not? It makes going back easier.
There are plenty of committed people in the world that don't have much money. With current gas prices, that's pretty much everyone now.
However, you also have to figure of the toll it may take on you. Though you have few students now, people tend to flock to things that are free. You're sure to bump into enough "window shopper" students, who just go for a bit of a sample. The number of students you have is surely going to boost significantly. It may get a bit overwhelming at times, and you may need some extra help from another qualified Escrima instructor, who you may have to hire.
Money could help you expand.
It's great that you don't care about the money. However, if you care about your students and your teaching influence, then you may need to charge. That doesn't mean you have to go outrageously high priced. You could just do a monthly plan, where no one's wallets are taking too much of a hit. All proceeds could go to the growth of your practice.
If you charged, you could toy with it a little, offering % cuts from monthly tuition to those who bring in new members or just help you with your cause (like hanging up flyers, business cards, etc).
It will allow you to take in a higher percentage of students with what many could consider an "honest effort". You can make it so your classes do cost something, but it isn't much, and could be even less. Tell your students of the opportunities for lower tuition. Allow them to take pride in your service to them. The students/practitioners are the life of any martial art. Let it be contagious.
Either path you choose, I wish you the best of luck.