There are several ways you could do this.
1. Free Advertising Network (e.g Buzzlord and Adgridwork)
2. Free Classified Ads
3. Submit to Ezine articles
4. Submit to a poetry site
and many more ways.
There really isn't a 'free' way to advertise your cab company online. Nothing online is free when it comes to advertising your company, and the closest thing you can get to advertising is to sign up for a free website and advertise your company on your free website.
You can find Christmas poems for free online at the Poems for Free website. You can also find a variety of holiday related poetry and poems online at TheHolidaySpot.
One can find New Year poems online from: Poets, Family Friend Poems, Poetry, Foundation, Poetry Society, Greetings, Poems for Free, Poetry - Love - Poems, Poems, Poem Hunters, Poetry Archives, All Poetry, to name a few.
www.servprousa.com and www.servpro.ca works for my small business, we advertise free here.
From government websites. Check with the state and local governments
Advertise your rental properties for free at rentalbrokerage.com
Vistaprint or Zazzle are some of the website that does free business cards. The setback is that they will advertise on your card by printing their websites on it.
If you want to advertise a hotel online in India. greedenholidays.com is one of the hotel advertising website in india. there you can add your hotel images, tariffs by yourself, it's free to register.
A good place for you to advertise your semi online is at www.sellyoursemi.com. They are a specialized classified venue. And they also offer free listings.
Go to sulit.com for international ads online, you can go on eBay. Myspace.com can also be use to advertise your stuff. Mulitply.com is another free ad website.
You can advertise a room for rent in the classified sections of newspapers or online. Some online places to advertise are EasyRoommate and New York SpareRoom.
Make a video on youtube, or advertise it on the forums