Wrap a GUI around it and package the program as a single executable. I'd suggest $15. Asking for $20 seems like too much (to me), but I've been told that I have bad judgement in such matters. :)
Also, I agree with others that trying to sell a CLI version will probably go nowhere. In fact, it may stifle adoption after you switch to the GUI version (since prospective users might think "Oh, that's that terminal program, right? Yuck!").
Also, I agree with others that trying to sell a CLI version will probably go nowhere. In fact, it may stifle adoption after you switch to the GUI version (since prospective users might think "Oh, that's that terminal program, right? Yuck!").