Software that's best for creating webcomics

[Twilight Yagami 16]

Hey,

 

So I am wanting to create an MSPA webcomic of my own and I am unsure of what software would be best for me to use.  I was thinking that I could use an illustrator software similar to adobe illustrator but I don't have the cash to actually buy adobe illustrator.

 

Does anyone here know of any cheap or free illustrator programs that I could use to produce my web comic?