I have two suggestions for you:
1. Find out who the most influential blogger in your area of business is. Use the money to pay for dinner with that person. During dinner, convince him to write about you (I expect you to have something worth blogging about in your company's bag). Often, it's enough to get that one opinion leader to put the word out. Other bloggers will then mostly pick up on the topic.
2. Find out where most of the influential people who you think would use your product are (for example the most important convention for people from the field that you do business in. Grab your marketing guys and girls and your graphics designers (and if you have none of them, grab yourself) and come up with a medium and a message that you would consider has the highest viral potential vs. the lowest cost, so you can produce many of these mediums. For example (this is just for explanatory reasons and I will not be able to take the time to think it through) you could print smart and funny business cards, designed like those flyer postcards which are used as an advertising medium, just as small as a business card, that have a blank space that people can fill in their name and occupation and use to introduce themselves to each other. These cheap, subtly branded and (in theory) viral cards could then be handed out guerilla style in front of the venue where the event is taking place and help spark interest among opinion leaders of your business field, resulting in some of them ending up as multiplicators by tweeting or blogging or just by talking about your thing.
As suggested by some people who answered your question, there are a lot of free things you can do for your marketing, too, though…
See the answer on Quora: