What are the Halachik issues in mailing a letter (i.e. envelope containing a sheet of paper, no money) on Yom Tov?
Assume for the purposes of discussion that there is no stamp being used since you might consider the stamp as similar to money. Instead, assume that either the envelope is metered or is business reply mail, both of which have no cash value.
[This question posted for discussion purposes. If I need a psak halacha, I will ask a rav.]