Price of gold is fairly stable
I do love me a bit of Ancient Rome. And I love the term Solid - it came from the solidus, a gold coin minted by Constantine 315AD
Domain have done some amateur digging and will try the following: in Neros day 2 denarii would buy a Modius, which was sufficent grain for ten days for one average male (two one pound loaves a day, there is a diet to make wheat intolerant weep)
Now the aureus was replaced by the solidus, but it was about 25 denarii. So we can say that one gold coin bought you about 100 -120 days worth of basic food.
A kuggerand is about four times the weight of gold as a aureus, and it's about £1,000 to buy today. And at £3 per day I could carefully feed myself. Certainly in bread alone.
So over nearly 2000 years, a gold coin is roughly enough to feed one man for three months.