Platinum tends to be worth more than gold by weight, but as prices  fluctuate, sometimes the gold price does go higher than the  platinum price.
To substitute for 1 egg you can use ingredients you already have. 1 Egg = 2 tbsp. flour 1/2 tbsp. butter 1/2 tsp. baking powder 2 tsp. water. Two years ago my daughter (who was 9) did a science project about this very subject. Basically, the eggs were binders to keep the cake together (and they did add flavor...).
Did you know you can substitute mayonnaise for eggs in your baking recipes? Mayonnaise is made with eggs, so it makes sense to reach for the mayo jar. The mayo adds moisture to your baking because of the oil, and it also adds a wonderful flavor. UPDATE: Youâll need to decrease the amount of oil called for in the recipe.