Nobody can force you to spend money you do not want to spend, and surely can not force you to spend money you do not have.
Who is doing the catering? If a bucharian caterer, it is important to determine if the hechsher will enforce all kashrus concerns ashkenazim have that bucharians do not. Your ashkenaz friends and family may not be able to eat altogether, leaving you with little to nothing to contribute towards the cost of anyones meals.