Going Ape! (1981)
There were 3 conditions to the 5 million dollar inheritance, and they had to be bathed twice a week.
When his father - who owned a circus - dies, Oscar inherits 5 million dollars - and 3 orangutans. However there's a condition connected to the money: if he gives away the apes or just one gets sick or dies during the next 3 years, the zoologic society will get all the money. So he not only has to deal with 3 apes and an annoyed girlfriend, but also with a greedy zoologic society's president.