Like this?
Cause still not working
Have you tried placing a condition in the workflow that saves the users bid to check if current bid < current price?
That would be a way to solve it.
So when you save, check to see if the data has changed.
do i need to use any custom workflow? if yes, how?
I have not used a custom workflow until now 
Thank you
No, I think you could compare a value you got when you did the read with the value there when you try to save.
yes, interesting if i would know how to do it, that would be even better 