What is the correct formatting or punctuation for an abbreviated slang type "and" in a phrase like "skittles 'n beans"?

Answer 1

Answer: skittles 'n beans

The shortened form of "and" is most commonly written as 'n (apostrophe before n).

The apostrophe takes place of the omitted letter "a" in the word.

Other Examples:

goin' (apostrophe takes place of the g)

same ol' stuff (apostrophe takes place of the d).