Price
The price is the odds offered on an outcome at a particular venue at a particular moment.
In plain English
Betting is buying a contract, and the price is what you pay for it. The same outcome can carry different prices at different books, and different prices at the same book minutes apart.
Example
One book offers -105 on a total while another offers -115 on the same total. Those are two prices for one opinion.
Why it matters
Two people can hold the identical view and get opposite results, purely because one paid a better price. Price is the part of a bet you control.
How V8 uses this term
V8 treats price as part of the claim rather than a detail. An instruction that depends on a price is only valid while that price is available.