There is no $ value (except as a collectors item), shillings are no longer legal tender in Britain.
The Florin (Two Shillings), is part of an obsolete currency used by Britain and many of the 50 plus Commonwealth countries. At Britains conversion to decimal currency in 1971, the Florin converted to 10 New Pence. At that time, the 10 New Pence was the rough equivalent of $0.26 USD or $1.45 USD today.
A Halfcrown is the eqivalent of Two Shillings and Sixpence. A Crown was Five Shillings.
There was no 1861 British Florin (Two Shillings) minted.
The sign for the British Shilling was an S if a sign was required. £1/2/6 or £1/2/6d represented One Pound, Two Shillings and Sixpence. The Shilling value is between the Pound value and the Penny value, so it does not need a sign. The position of the 2 makes the value Two Shillings. 2/6d represented Two Shillings and Sixpence. The Shilling value precedes the Penny value, so it does not need a sign. The position of the 2 makes the value Two Shillings. If the need arose to indicate an even Shilling value, it was written as 2/-, indicating Two Shillings and zero Pence or, 2S, indicating Two Shillings.
The sign for the British Shilling was an S if a sign was required. £1/2/6 or £1/2/6d represented One Pound, Two Shillings and Sixpence. The Shilling value is between the Pound value and the Penny value, so it does not need a sign. The position of the 2 makes the value Two Shillings. 2/6d represented Two Shillings and Sixpence. The Shilling value precedes the Penny value, so it does not need a sign. The position of the 2 makes the value Two Shillings. If the need arose to indicate an even Shilling value, it was written as 2/-, indicating Two Shillings and zero Pence or, 2S, indicating Two Shillings.
It isn't silver and isn't a dollar. What you have is a British crown (worth 5 shillings in the old Pounds/Shillings/Pence system, 1/4th of a British pound, or 25 new pence) and is made out of copper-nickel. It is a very common coin and doesn't sell for all that much. It is worth about a dollar or two if completely uncirculated and about 50 cents or so if scratched or worn.
At the time of Australia's conversion to decimal currency in 1966, an Australian Two Shillings (Florin) converted to an Australian 20 cents. At that time, Two Shillings Australian was equivalent to Two Shillings British.
Such a coin does not exist. The Florin (Two Shillings) was first minted for general circulation in 1849.
The British Military Authority Two Shillings and Sixpence note was issued from 1942 for the duration of WW2 and for the subsequent occupation forces. A British Military Authority Two Shillings and Sixpence note, in very good condition, might fetch anything up to £12 GBP. A reputable coin dealer will be able to more accurately identify the note and make a valuation.
All British Florins (Two Shillings) were made from a copper-nickel alloy from 1947 onwards.
The 100 ptas coin is a Spanish coin. The British Halfcrown coin has a face value of Two Shillings and Sixpence. To get a valuation on either coin, you would need to provide the date and condition of the coin.
Such a coin does not exist. The British Florin (Two Shillings) was reintroduced into the currency in 1848 as a tentative step towards decimalisation, a Florin being one tenth of a Pound.
There were at least two major types of money in use in the colonies before the US became independent and eventually established the dollar as its currency. Many places obviously used British pounds and shillings, but Spanish "reales" ("royals") also circulated widely. In fact, the US silver dollar's size and value were chosen to closely match the Spanish reale.