Student or Learner
"Would you be willing to sell this for a smallish fee?"> What does "smallish fee" mean? How much ($ range) is smallish fee?
I searched for the word smallish fee and it seems like it is a self invented word that is not standard English.
It doesn't refer a specific range of prices. A small fee would be subjective. It depends what you're paying for. "Smallish" is used a lot as are many other adjectives followed by "ish".
It's not a "self-invented" word! That would mean that the word invented itself. That's not possible.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.