Are there any legitimate opportunities to make money stuffing envelopes?

No, envelopes are stuffed by machine a lot cheaper then it would cost to pay someone.

They are out there if you look. I often do env. Stuffing and handwriting addresses for a company and they pay $75 per batch of 500. You get a batch a week. This is also contracted work, so there are no taxes taken out, so you have to be mindful of that... but that is only if make more than I think $500/year... I only do it for extra funds around Chirstmas time and what not, but there are some companies available... the work I get is for non-profit agencies who are mailing out asking for donations, and typically handwritten notes get better response... Typically I have learned if you have to pay anything to participate, it is a hoax. I only had to go through a training and have my handwriting approved as "neat". Good luck. I work through DNR group... but don't know if they are everywhere or not.