Stupid question about rakeback..

[meHIGHyouLOW]

I finally got my 25% rakeback deal from cashgames and tournaments. Directly to my poker account in start of each month. First is this a good deal?(im not the affiliate or what ever its called so dont PM me) And 2nd is this the way count how much i get back/hand.
Situation:
10players table i fold preflop couple of guys go to end raising and the rake $3 so do i earn here 3/10*0.25 or do i have to invest to pot(by blinds or bets) to get rakeback?

Thx
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