Adwords seems the most logical choice. I'd spend $20 and buy Perry Marshall's Adwords book and learn how to do split testing. With a $1000, you shuld be able to generate enough impressions to figure out what keywords work, what your competitors are doing in Adwords, and have a handle on what your landing pages are doing. Once you have that then you can more ably spend the next $1000.
Here's that Perry Marshall book: http://www.amazon.com/Ultimate-Guide-Google-AdWords-Million/...
Therefore personally I prefer investments that have a potential for growth - like a press release might make bloggers write about my product, which might increase it's page rank and give an enduring boost to visitor numbers to my site. A google ad does not increase page rank.
Sure, with Google Ads it is simple maths, but my impression was also that it is very hard to make money with adwords. For example I was selling a mobile application where I would have earned about 2€ per sale, but relevant keywords cost around 10cent. So even if every 20ieth clicker would have bought the app (a very high conversion rate, I think), that would only have been the break even point.
As for the press release, I wouldn't spend 1000$. Actually one can make them for free, but with my app back then I just felt it might be good to pay someone who is more skilled at writing to do it.
And I never thought anyone meant to spend all $1000 on a press release :)
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