Is there a time in the past where prices were stable for generations? Or was there inflation even before currency (This sack of potatoes will now cost you 13 eggs, not 12...)
I guess the question can also be 'how big can an economy be before inflation appears?'
Inflation is the result of too much money chasing too few goods.
The example you gave with eggs isn't an example of inflation because eggs are not a currency. What that actually is is fluctuation in the value of a good relative to another.
I guess the question can also be 'how big can an economy be before inflation appears?'
It doesn't really have to do with the size of the economy, it has to do with the availability of currency in an economy. In Roman times for instance, debasement of coins led to prolonged periods of inflation, while in Medieval times, the lack currency caused centuries of prolonged deflation.