You know, I’m making site for freelancers.
I wanna do some calculation realtime when freelancer entering price for a new service.
When he choose in select component 1000 I wanna show him final price 1250 in the text field below.
The current table I edit is Services (not Users).
Actually, just re-reading what you wrote - the price is being entered. So there is no need for the relation + lookup. All you need to do is write the entered price to a user specific column, and then do the math directly.
The key is the user specific column, because the values are written as soon as they are entered, which means you can use them to perform calculations. With a native add form, you can’t do this because the new row isn’t created until the form is submitted.