This is probably the simplest and most effective way of driving traffic, make that targeted traffic, straight to your site when they want what you have to offer!! Sounds great? It is, but its not free... Google Adwords and bidvertiser advertising work on sort of an auction basis where you bid on keywords or phrases and according to how high your bid is compared to all other bids, this decides (among other things, like google rankings, etc) where your ad appears in the search results for any keywords or phrases you've selected.

Its not that expensive and is definitely worthwhile but if you're broke to start with dont go into debt for Google Adwords, there are other ways, they just take a little longer.