This may need some attention to get it, or it may be too easy for the community.
My prefix sins, refutes, and help you see,
My infix you won't bother to count.
My suffix tells you if something's good or bad,
And you'll get it if you do it!
I think the answer is
Concentrate
My prefix sins, refutes, and help you see,
Con - which can mean to deceive or trick someone (sins), an argument against something (refutes) or to study attentively (helps you to see).
My infix you won't bother to count.
Cent - a monetary unit in various countries, equal to one hundredth of a dollar, euro, or other decimal currency unit, a very small value.
My suffix tells you if something's good or bad,
Rate - which means to assign a standard or value to something according to a particular scale.
And you'll get it if you do it!
Concentrate - a substance made by removing or reducing the diluting agent, made by concentrating.