Not sure about being able to sort, but yes the price can be put in comments,
or on each line …
https://en.numista.com/help/how-can-i-register-my-collection-on-numista-1.html
4. A window opens, where you can enter information about your coin or banknote. All fields are optional:
· Select the version, or “undetermined” if you don't know or if it is not relevant for you.
· Select the grade.
· Enter the quantity: if you have multiple identical coin, you can enter the quantity here, or you can enter “1” and register your other coins separately.
· Enter the price at which you bought the coin [bill].
and so on …