Arcane Ammunition Boon, how does it work?

[Steven_Evil]

The Boon:

You have a special contract with an ammunition crafter, and you are able to order small batches of specialty ammunition as a result. You may purchase +1 corrosiveUE, +1 flaming, +1 frost, and +1 shock ammunition in sets of 10 instead of sets of 50. You can cross this boon off the Chronicle sheet at the beginning of an adventure to gain 5 pieces of this ammunition in any combination for free; this free ammunition has a sell value of 0 gp.

Does this mean I can infinitely buy the smaller lots, or is it a one time use to get a lot of 50, but split into the combinations listed?

So, with that, what is the cost of buying the smaller lots? The price in the CRB is listed for 50, there aren't any price options for just 10. I myself am going to be using this boon in the future, but I also have a player that wants to apply it to a character and wishes for clarification first as to what the pricing is.

[UndeadMitch]

The boon lets you buy lots of ten of the listed ammo types. You can cross the boon to get 5 ammo of any combination of the listed types for free. Until you cross the boon off for the five free ammo, you can keep buying lots of ten. Once you cash in the five free ammo, you lose the ability to buy lots of ten. The price would be whatever the price for a lot of 50 is, divided by five.

[Steven_Evil]

Ok thanks! That's what I thought but I wanted to make sure that it was correct before I informed the player.