I'd buy Market Samurai. If you sign up for the free trial you'll receive a discount. I believe it's discounted to $97. Great keyword research tool which will help you rank for longtail keywords. (If that's the route you'd want to go.)
Only 100? It really depends, probably spend the first 20 on a domain name and the first month of hosting, another dollar on a first month 1 dollar aweber service. Take 50 dollars and outsource the creation of an in demand topic supported by either forum boards or blogs and take the remaining 20 to get a decent theme and setup for my web page. Then go into my market and self promote the heck out of my product. Talk on blogs, try to do interview webinars with authority figures. Ask if people would be willing to give my book away to their buyer list if they would be willing to direct people to your sign up page. Stuff like that and recoup my 100 dollars and repeat. OR I would take the 50 dollars and try to get 10 high quality articles written. Submit them 2-3 at a time to ezine articles then rewrite them and create blog posts, squidoo pages, social bookmark them, rewrite them again and submit them to ezine articles and other article directories. Have all the traffic go to a mail list sign up page. OVer the course of two months I should havea couple hundred people at least then I could survey them and ask them what they are looking for create the product and sell it to them.. OR Waste it on Games, Women, and Liquor ...Whatever suits your really
Nice ideas Exvignola, really liked your games, women, liquor spin in the end. Although I donno how much you can have each of those in a $100! A lot fantasy questions are like what would you do if you were given a 'million dollars' such and such...people begin to dream and fly into them. But when you have like a $100 in your hands, you can't dream! No music will be playing in the background. You have to think practically. You can't waste that precious little you have! You have to turn that $100 into a $1000 in a week or a month! Now thats a challenge don't you think? That is why I have asked this question Genesis1.
If you already have websites, you can use it for SEO. Good SEO will double/triple your revenue. Or you can create micro niches.
Eat and drink out on a saturday night and then go for movies. Put some fuel in bike and car. Nice, when are you giving me 100? lol
If I had $100 extra to invest in my business I would consider 2 things.Do I need results within a week, or do I want results within 3 months? For quick income I would promote an affiliate product in ezines (solo ad) and for long term income I would invest in a keyword software called Micro Niche Finder.
Try to start your own business. If you don't have an idea right now, save this money and think over the idea for your business.