Pacific Mail steamship cancels are very sought after. You normally encounter them with 1-3 strikes of the cancel on a stamp. As a general rule, the more identifiable strikes on a stamp, the higher the market value.
Also, the greater the visual contrast between cancel and stamp, the better. For example, since virtually all Pacfic Mail cancels are in blue ink, the examples on 2nd issue revenues and the $3 denominations of the 1st issue do not make as aesthetically dramatic presentation as those on the $1, $2, and $5 denominations of the 1st issue or the 3rd issue revenues.
This example, with 6 clear strikes from the steamship 'Rising Star' makes for an exceptional visual presentation. The Rising Star is one of the more common steamships as far as the cancels are concerned.
PMSS-canceled pieces normally range from $40-60 at the low end, bearing 1 or 2 strikes, up into the hundreds of dollars depending either on the scarcity of the ship in question (e.g., I have yet to find an example from the steamships Sacramento, Ocean Queen, or Oregonian) or the number and clarity of the cancel strikes.
At retail this would likely be around a $250 item even though the stamp itself only catalogs $40.