Clue: Basic skill with money in 10? (8)
Answer: RUDIMENT
Explanation: Definition: Basic skill
An envelope ('in') of DIME ('money') in RUNT ('10?'; like 11/22/6 HAM-LET is, by synecdoche, a little pig, and there is another layer here, that a little pig is an example of a RUNT, which accounts for the question mark.