Translating sums of Roman money into modern ones is just not working, the numbers won't give you any real picture. This is because the value of our currencies change very rapidly and due to the fact that most services and materials had very different values back then compared to today. Most things are very much cheaper today (as how much bread you can buy for one hours work)
I prefer to compare Roman sums of money to how many kilos of say pork or how many sandals you could by for one hours decently skilled labour. Now these kind of numbers are difficult to find (Unless you use Diocletianus price edict from the early 4th century) but it's worth the trouble in my opinion. I would post a more elaborated argument if I had the time, I'll try after my exams next week.
Do you think it's cheaper now ? Surely it would have been cheaper then, you had slaves and all you had to do was feed and water them.