This country actually makes coins for its own use, so they can be found
circulated.  In fact, with many if not most of the L.s.d. coinage it is extremely
difficult to find perfect Unc specimens.  (And then when you find them they're
really hard to sell at those astronomical prices in the catalog.)
Let's do a brief historical survey before going into the numismatic details.
The original inhabitants were a mixture of Melanesians, thought to have
emigrated from the west before the common era, and Polynesians traveling from
the east somewhat later.  These peoples now make up a bit less than half of the
total population.  First European sighting was by Abel Tasman in 1643, first
contact by James Cook in 1774.  Extensive mapping was done by Captain Bligh.
The two big islands, Viti Levu and Vanua Levu, were richly forested in
sandalwood and the coastal shallows were filled with beche-de-mere, culinary
delicacy to the Chinese.  These products made for a convenient stopover for
ships playing the China trade.
By the mid-nineteenth century British interests were dominant, and the
islands were annexed to the Empire in 1874.  In the British scheme the colony
was to be a major sugar producer, and to this end many thousands of workers
were imported from India.  The Indian community prospered and grew until today
it forms the largest ethnic group in the country.  The British provided a degree of
infrastructure to the large islands, and this was improved when they were used as
a major staging area for the Allies during World War II.
A push began for independence after the war, culminating in 1970 when
Fiji became a dominion within the British Commonwealth.  Though the economy,
based on sugar and tourism with a dollop of gold mining, was and is reasonably
stable, there has been ongoing ethnic tension between the Indians and the native
Fijians.  The Indians had controlled the economy and government, while the
constitution granted over 80% of the land to the natives, who by independence
made up less than half of the population.  This antagonism bore fruit in 1987
when a successful pro-native military coup was carried out.  The military
government took the country out of the commonwealth, and now it is on its own.
The big islands were rich in the pre-European period, and there was much
gifting using various kinds of so-called "primitive money."  Typical items
presented were tapa bark cloth, fish hooks, salt, shells.  The top of the line items
were orange cowries, Cyprea aurora, and tambua, the latter being a sperm whale
tooth (or carved wooden imitation) artificially colored red and placed on a string.
To the Fijians larger tambua were better, so the wooden imitations were often
preferred.  Tambua trade was encouraged by Europeans and Americans, who,
being at the time fanatical whalers, had access to lots of teeth.
Today the tambua show up from time to time in the "primitive money"
market, where they get $300.00 or so.  The orange cowries are very scarce, and
original strung shells of the nineteenth century are very rare.
European style coinage was inaugurated in 1934 with copper-nickel
halfpennies and pennies and silver sixpence, shillings, and florins.  As was the
normal British practice, the colonial coins were valued a bit lower than their
homeland counterparts.  All of the prewar and wartime coins are easy enough to
find in circulated condition, anything up to, say, XF.  Uncirculated coins are, in my
experience, rather excessively rare.  Almost every piece I've seen so described
was "iffy," AU++ at best, and who would want to pay three figures for a coin which
will only be a problem when it's time to sell?  I imagine unquestionably Unc coins
would get the money in an auction, but AUs get the XF price if you're lucky, and
XFs usually sell at a discount.
These comments don't apply to the San Fransisco coins of 1942-43.
These are common in Unc, except for the brass pennies and halfpence, which
often come with spots.  And you can't compare these coins with the British issues
to decide if you have an expensive British Unc, as the striking characteristics are
quite different.  San Francisco coins are nice and sharp, while the British pieces
are a bit shallow on the portrait.
Brass 3 pence were introduced in 1947.  George VI's 3 pence are tough in
Unc, but those of Elizabeth are common enough, subject the usual proviso about
spots with this vulnerable alloy.  No silver coins were struck after the war, being
replaced with copper-nickel versions starting in 1953.  All of these copper-nickel
coins can be found fairly easily in Unc.
There are numerous proofs of the L.s.d. series from 1934 through 1965.
All are rare.
Fiji abandoned the pound for the dollar (tied to Australia) starting in 1969.
Most of these coins were issued in decent quantity, but export to wholesalers has
been spotty, there being no big numismatic dealers there.  Consequently you will
find yourself having a devil of a time filling in the holes in your date set.  It's
frustrating to be waiting for years for a coin valued at .75, but that's the way it is.
Some of the 20¢ and 50¢ coins of the 70s are now almost impossible to find in
Unc, and the 1978 50¢, with mintage of just 4000 odd, will one day be a rare key,
when Fiji booms (which doesn't look to happen soon).
Decimal mint and proof sets issued since 1969 can be easily acquired in
Australia, but here in America they are not seen very often.
Most of the Dominion commemoratives are reasonably easy to find in
copper-nickel and silver.  Typically the proofs are easier to come by than the Unc
versions.  The gold commemoratives tend to be somewhat less common in gold
circles than, say, Caribbean gold.  The bullion issues of 1990, struck from
unrefined native gold by the military government, are available on the secondary
market.  They are very striking and pretty and more dealers took a chance on
them.  You'll have to ask them if they sell.