Postage meter: Pitney Bowes - $20/mo. not including postage. (most people DO NOT want to absorb that kind of expense... being I work from home, I use it for business also which justifies the expense.)

Supplies: any office supply store

Post Office will GIVE you any Priority supplies you need as it encourages you to use the "higher" rate. You can have them delivered using this link:
http://supplies.usps.gov/priority.htm
We just pick ours up as needed.

The assistant? Try the local college. I have an Honors student and she is GREAT