"Ancient Rome" is a bit of a broad category, but there are some general categories we can talk about.

• Land: I'm not so sure land actually counts as a way to store wealth since you would need a buyer to sell it all, but it was definitely something in which one invested wealth. This would include the cost of slaves, etc.

• Bullion: Particularly in the later empire, coins which were collected for tax purposes would be melted down into bars for transport and storage.

• Trade and commodities: Grain in particular was a worthwhile investment, particularly if you had it in a year of famine.

• Civic expenditures: If you were wealthy, you were expected to spend your money on games, the grain dole, etc.

• Coin: during the imperial period (and into the middle ages), the ability to mint coin, particularly gold coins, was an imperial prerogative. Rome had a highly monetized economy, meaning coins were used at all levels for trade. The imperial solidus was the default measure of wealth from the fourth century onward.

For the purchase of a villa, the price would be paid on whatever grounds you had made the exchange: land, bullion, or whatever. There was no one method.

Some further reading:

• Brown, Peter. Through the Eye of a Needle: Wealth, the Fall of Rome, and the Making of Christianity in the West, 350-550 AD. Princeton, N.J: Princeton University Press, 2012.

• Naismith, Rory. “Gold Coinage and Its Use in the Post-Roman West.” Speculum 89, no. 02 (April 2014): 273–306. doi:10.1017/S0038713413004533.

Well, the Romans had banks and moneylenders - some of the most influential members of Roman society had had problems with loan sharks; Cicero once blew 14 million sesterces he didn't have on a massive town house, for instance, and had to spend the next few years taking on dodgy court cases, like defending people who'd taken part in the very conspiracy he'd recently uprooted (one of whose aims was to cancel all debts in Rome, ironically), to pay off his own enormous debt.

Most private citizens had their own treasuries, though - numerous big bronze strongboxes have been found in Pompeii which would have contained huge sums of money kept under lock and key. When money from these strongboxes had to be moved around, they were usually kept in chests, which the slaves would be entrusted with lugging around.

Also, as far as the state was concerned, state funds were usually kept in temples, like the treasury of Saturn at Rome, where a mixture of religious reverence, patriotism, and large, bolted, bronze doors would ensure that the Empire's funds were kept safe.

As /u/purplearmored mentioned, david graebers book "debt the first 5000 years" is interesting on this topic. He is an anthropologist not a historian, looking at how markets, dept and exchange work in different situations across the world and in history. I cannot remember how much he talks about Rome but it is relevant in general.

His argument is basically; people miss the point when thinking about how people managed before there was money. You only need to use gold if there is no way of building a community. So in cities, people were able to keep ledgers and buy and sell in gold as the denomination, with out actually having any gold at all. It was just added to a tally and your standing in your community was based on if people thought you could return your depts. So in large part your wealth was not something your stored in coin but how many (important) people owned you a dept - be it a wife, their life or a business deal that was still ongoing. Of corse you would have had land etc as well, but people underestimate the power of cross depts, and anyway how do you keep hold of your land if no one will help you defend it?

In fact he suggests that money as in gold or government backed notes were really only ever a product of wars. For most people gold was a disadvantage in trade, why spend time developing relationships with customers and clients only to demand they pay up in full and there for sever the need for future relationships? Especially if they settle it with something that you cannot eat/make tools/use to protect you form harm, and will leave you open to robbery. This sort of trading also solves the problem of liquidity. No need to carry cash, no need to wast time mining it, no problem if it runs out.

The time when this dose not work is when there is no chance to build trust e.g. in war. He describes quite neatly how war creates cash. You invade, you need to feed your army, no one trusts your soldiers, you give you soldiers gold, you tax the invaded land for gold, they are forced to find gold, they sell food to the soldiers - for gold. So you sort out your supply chain without needing to even set one up. And you get your gold back.

I hope this helps, I am not a historian, and would not normally try and reply on this sub. I am also aware this sort of side steps the "vast amounts" part of your question as far as spending goes. But I think that is is because you have to think of money/wealth as interlinked with power at which point it becomes easier to understand what people did with their money/power, they exerted power over people and tried to build more power.

This is a good talk by him at google http://www.youtube.com/watch?v=CZIINXhGDcs

Not a historian, just recommending Debt: the First 5000 Years as a good read for anyone interested in this topic.

Coins that were being used during ancient Roman times were made with intrinsic value. They are mostly made of gold, silver, copper and bronze. Most of the wealthy families during ancient times stored their wealth in their own houses/homes. http://en.wikipedia.org/wiki/Roman_currency

Coins were normally used for celebrative purposes. The first coin romans minted was in Naples when they got rid of the Greek fleet in the year 454 BC. Similarly coins were used to celebrate members of the triumvirate like Octavia and Mark Anthony and later on emperors themselves. On the other hand, coins were used as financial tool as well and the most popular was the Roman sextertius which was made of a bronze alloy