Gold, silver and platinum proof coins, plus uncirculated "mint condition" versions in non-precious metals go on sale on Monday ahead of the tender's full roll-out on March 28.
Prices range from £10 for the uncirculated coin to £1,995 for the gold proof two-coin set.
The coin's design pictures the Welsh leek, the Scottish thistle, the Northern Irish shamrock and the English rose emerging from a royal coronet.
It was created by David Pearce, who was just 15 when it was chosen to feature on the coin, after he beat more than 6,000 other entries submitted by the public to a competition in 2014.
Dr Kevin Clancy, director of The Royal Mint Museum, who helped choose the design, said: "The winning idea combined traditional elements but also symbolised a modern United Kingdom in an elegant and a succinct way.
"It was a young person's interpretation of an idea while still being steeped in history and tradition."
As well as being the same shape as the old threepenny bit, the new £1 is hoped to combat counterfeiting.
Collectors can buy the coins from http://www.royalmint.com/