It's not free per se (lots of 30 day trials out there for it), but there are plenty of ways to get the full version for free - Paint Tool SAI. Whether this can be used to fit your needs, I'm not sure. Some time ago Photoshop CS2 was offered (FROM Photoshop's site) for free. I doubt it's there anymore, but likely VERY easy to come across these days because of that. Other than that, I stick to whatever free software comes with my tablet or the like. Sorry if I couldn't be of more help!
It's not free per se (lots of 30 day trials out there for it), but there are plenty of ways to get the full version for free - Paint Tool SAI. Whether this can be used to fit your needs, I'm not sure. Some time ago Photoshop CS2 was offered (FROM Photoshop's site) for free. I doubt it's there anymore, but likely VERY easy to come across these days because of that. Other than that, I stick to whatever free software comes with my tablet or the like. Sorry if I couldn't be of more help!