Everyone seems to have heard about making a small fortune with envelope stuffing. However, in all the research done currently, no one has been found yet actually making a profit doing this job.
These days, there are a lot of small ads online recruiting people to do the job of stuffing envelope. You might wonder if it is a way for you to make some extra during your spare time. The short answer to your question seems to be no. Envelop stuffing is a scam which has been an extremely successful one in the past. One might end up out of pocket, with no recourse and a great deal of frustration.
So before looking to further explore the issue, get wise. Most disreputable companies ask people to make a payment in advance. Then envelopes will be sent to you with specific instruction given. One will be told how to stuff the envelopes, position the label, etc. Then the unsealed envelopes need to be returned to the company to have them checked.
However, most of the time, your stuffing skills will fall short and they will deem the work unsatisfactory even if all the instruction on the letter are well followed.