Lettering is quite easy depending on the program you have. There is Clip Studio; its lettering capabilities are okay, but not the best...
Affinity is having a 50% sale on their programs right now(ends June 20th)- you can get Affinity Designer, which is the (sorta)equivalent of Adobe Illustrator for $25(original price is $50). I use Illustrator for my lettering- it's the best of any of the programs out there used for lettering, but it can also be expensive...I picked up Designer, but havent used it yet. It's a one time payment and its updates are free.
As far as free programs for lettering, there are a few- like Inkscape, but you kind of "get what you pay for"...
For fonts, check out Blambot- he has some pretty good fonts that you can use for FREE, specifically designed for indie comic creators.