I buy sets of 6 Kwikset lifetime warrantee deadbolts and locking door knobs, I have plastic boxes that hold all six sets and I rotate them.

If you start typing, slowly, the first few letters of the name you want to mention, a drop box will appear below giving you a choice of names to select.

A couple pennies a piece at Kinkos, a box of rubber bands and go hog wild.  

Not everyone see's all the messages, but most people get pm's straight to their email box.

I feel like a PO Box defeats the whole purpose of having a "normal looking" envelope with a letter in it. 

Other than people living in the basement.While cleaning out an attic of one property I found boxes of complete loan packs complete with all pertinent personal info including SSN #'s.

Today I'm working on emptying boxes and getting the office put together.

If you decide to go without an office, I would get a PO Box somewhere offsite for rent checks, inquiries, etc. and then set up a good website.

A visit to one of their offices shows people walking through the door and picking up a list of properties in a box and leaving with that list without speaking to anyone.

You can see this in posts here where someone is so far off base in thinking they can do something in RE.I recall one post where a member was wanting to do his marketing to people who had received a quit claim deed, I like to see imagination, thinking out of the box, but that is in another universe because he had misconception of what that deed actually is and when and why it is used.