$100, £50, etc. a throw
Definition 1 of 1
Pro Tip 1/3Casual Speech
This phrase is often used in informal, conversational settings rather than formal writing. 
At the craft fair, those handmade scarves are going for $30 a throw.
Pro Tip 2/3Common Misuse
Avoid using 'a throw' for non-countable items like sand or water; it's primarily for countable, discrete things. 
Each hand-crafted mug from the potter costs $45 a throw, not to be confused with sand sold by the pound.
Pro Tip 3/3Per Unit
The phrase emphasizes the cost per individual unit or occurrence, with a slight nuance of repetition or multitude. 
If you're buying cookies from that bakery, they're $2 a throw.