I would not use silver to compare prices from that long ago, silver and gold were both cheaper than today.
I would use the salary for a day labor instead. Like if I spend my salary for a day on just nails, vs how many nails a smith could make for the same number of working hours.
Sure, but that means the Roman cost would be even cheaper. If silver was cheaper in Roman times, and iron was 1/300th the cost, then the Roman nail becomes even cheaper (which doesn't make sense)
I'm not sure what the hourly rate for a day laborer would be. $20/hr?
I think the real issues with this calculation are the idea someone can crank out 2,300 nails / hour. I think 1 per minute (sustained) seems much more reasonable.
That makes the labor cost 40x more. And maybe it would be a semi-skilled occupation, so $20/hr or $40/hr makes more sense. So now the labor cost is 150x more.
I would use the salary for a day labor instead. Like if I spend my salary for a day on just nails, vs how many nails a smith could make for the same number of working hours.