No problem, snapshot fields to the rescue.

https://help.quickbase.com/user-assistance/setting_up_snapshot_fields.html

But you will need to change from a system variable to a table of prices. I gather that you have very few prices, so they are probably an hourly rates. So I will use that an an example.

Make a table with 1 record in it, Add the record and then block all users, even admin from adding or deleting.

Make fields for your Prices and then edit the record to fill in the prices.

For example

Lawyer Hourly Rate $600
Paralegal Rate $ 250
Photo copying rate $50
Quick Base Developer Rate ... etc

The record will be [Record ID#] because there is only 1 record.

Make a relationship to the detail table and let it create a new field for you for that Relationship

Then edit the field to rename it [Link to rates (=1)]
and then change the field type to be formula numeric with a formula of 1.

Lookup the rates by label them like

Lawyer rate (lookup)

Then make a duplicate set of fields naked like

Lawyer rate

and edit the field properties to make them a snapshot of their respective lookup field. The magic is that the will "snapshot" or freeze the lookup field value at the time the record is created, and not subsequently change when the lookup field changes.

Forum Discussion

Price Change Problem