If you give a gift instead f money then they will never know how much you paid for it no matter what the value is. You might have gotten a cheaper bulk value and they will never know how much you feel they are worth spending on a gift for them.
My opinion is to always buy them a gift and not cash or a money gift card to a place and the product gift handed over and looked at has real value and shows real appreciation to the person given too even if it costs a mere few dollars. Otherwise you would need to start heading up starting from minimum $18 to $100 and maybe even a $1000 cash gift card to be enough to prove to the person your appreciation for them or they’re value for birthday etc….