The first thing you need is some product. Get some recordings out there and tell people where to find them - the first thing people will ask you is "What do you sound like" and pointing them to some online content they can listen to is a gazillion times better than saying "Sort of a cross between Katy Perry and Lamb of God".
Gig photos - good ones, not "This is our drummer throwing up outside the club last week" - get them out there
Reverbnation.com is free - I have recordings, photos and vids along with my gig schedule there.
Use Youtube - even if it's a photo montage over a reasonable quality recording rather than a performance video - it's free. Windows Movie Maker is adequate for this sort of thing - again, it's free.
Use Twitter/ Facebook/ Myspace - talk to people, especially wedding planners, event planners, venue management. Point them at your material. - all these social network sites cost zero dollars.
So far, you've not had to spend any cash.
As you're all working, pool some cash and:
1 - get some CDs duplicated so you can hand them to people who say "What do you sound like?" Make sure track 1 is your best song because if the person you give it doesn't like track 1 your CD goes in the bin without track 2 getting a listen.
2 - get some flyers printed - good photo, brief band biog and say what you sound like
3 - business cards are always good. Put them up on shop notice boards - I put one up today in the local farm shop so that people can see it whilst they're picking the meat for their BBQ party.
Entertainment agents - Register with some of the "Single fee per year" people who cover your area. I spent Â£40 registering with a site in London in April, and I've had to turn down four of the last six enquiries that have come from that site because of being double-booked.
Do have a press pack ready too.
Go see bands. Give them your material and talk to them about suporting them at their gigs to get you exposure.
Marketing your band will take up about 50% of your free time. It takes up about 50% of my waking hours.
And enjoy it, because the next day you need to do it all again.
"Be good at what you can do" - Fingerbanger
"I have always felt that it is better to do what is beautiful than what is 'right'" - Eliot Fisk
Wedding music and guitar lessons in Essex. Listen at: http://www.rollmopmusic.co.uk