Being comp.editors, and I want some fun with editing:
"A$$ yields ARG=65 ($ is esc key)
"A\$$ inserts "65" into current edit buffer
65i$$ inserts "A" into current edit buffer
"Ai$$ also inserts "A" into current edit buffer.
16qo"A\10qo$$ would insert "41" as we have shifted to base-16 and back to base-10
iA$-M@t$$ yields ARG=65
this one works by inserting "A" into current buffer, backing up to it, and then fetching
the edit buffer character.
Yes, PMATE is a TECO variant.