I'd like to buy gold in small amounts (1 gm) when the prices are attractive, but I can't keep a watch on it. I'm buying gold as a long term investment / hedge, and I don't have plans to sell it. Liquidity is important, but ability to checkout gold can be optional. What's the best strategy for me to buy gold?

Are there any services where I can request auto-buy units (say, 0.1 gm steps) whenever the price goes down 1%, or so.