Where do you advertise commercial spaces for lease?

[Matt Lefebvre]

Hello everyone!  I represent a client with a variety of properties under management.  Most of these are large apartment buildings, but some of them are mixed use buildings with some small retail/office space available (think 1000 square feet or less).  Bigger spaces are easier to lease because I can afford to invest money into marketing or split a fee with a broker representing a tenant... however as these are a variety of small office and retail spaces, I'm looking for low-cost advertising solutions.  

I've already put ads up on Craigslist and Loopnet, but how else does everyone market these spaces for lease and not break the bank?

Thanks in advance!