Ancient republican, imperial, and provincial currency.
Refer also to my page on ancient coins.
There are three different categories on eBay dedicated to ancient Roman coinage: Roman republican (category 3365), Roman imperial (category 4734), and Roman provincial (category 4735).
The coins with the most biblical connections will fall in the category of Roman imperial.
Roman coins were more than mediums of exchange; they were vehicles of imperial propaganda. The circulation of Roman coinage, bearing Roman symbols and the likenesses of Roman emperors, represented Roman power and dominion, a fact not lost on certain independently minded individuals, such as Jesus of Nazareth, in certain independently minded provinces, such as Judea.
The standard gold coin was the aureus. It was first struck at about the time of Julius Caesar and continued to be struck until Constantine (308-337) replaced it with the solidus. The aureus was equal to 20 or 25 silver denarii. Its weight steadily decreased over the years.
The standard silver coin was the denarius, first struck about 211 years before Christ. It was discontinued in about 296. It took 20 or 25 denarii to make an aureus.
The denarius issued by Tiberias Caesar (14-37) is also known as the tribute penny, based on Matthew 22.19 (Jesus speaking): Επιδειξατε μοι το νομισμα του κηνσου. οι δε προσηνεγκαν αυτω δηναριον (show me the coin of the poll-tax. And they brought him a denarius). Refer also to Mark 12.15 = Luke 20.24a.
The sestertius was a bronze coin worth one-fourth of a denarius. The dupondius was a brass coin worth one-eighth of a denarius. The as was also made of brass, and was worth one-sixteenth of a denarius. The quadrans was made of copper, and was worth one-fourth of an as (hence its name), or one-sixty-fourth of a denarius.
The quadrans is known in the Bible from the rate of exchange given in Mark 12.42: Και ελθουσα μια χηρα πτωχη εβαλεν λεπτα δυο, ο εστιν κοδραντης (and a poor widow came and threw in two lepta, that is, one quadrans). It is also known from the dominical warning in Matthew 5.26: Αμην λεγω σοι, ου μη εξελθης εκειθεν εως αν αποδως τον εσχατον κοδραντην (amen, I say to you, you shall not come out thence until you have given up the last quadrans). The parallel in Luke 12.59 names the Greek lepton instead: Λεγω σοι, ου μη εξελθης εκειθεν εως και το εσχατον λεπτον αποδως ( I say to you, you shall not come out thence until you have given up even the last lepton).
The most famous issuing authorities for Roman coins were, of course, the emperors.