Spending money on the poor

I want to know about urdu word "nazar e muyyan", people sacrifice animals if they are ill, or calamity stricken and want to get out of difficulties.

Note: This is done without any commitment. There is another type of commitment that if I succeed I will spend such and such on the poor. I am asking about the 1st type. Does it have any relavance. If that is true, can I spend money because I cannot sacrifice an animal because of living in a foreign place?