we have 2 dogs, so i know what we pay for them... not sure what cats cost though...
depending on where you live will depend on the cost of the pet food...
i live in Discovery bay and the pet food here is much more expensive than in say... Yuen Long...
i usually buy my pet food on HK island and transport it back to Db...buit my two dogs are quite big and so eat a lot of food....
if you are talking of only buying 1kg of cat food at a time, then it should not bee too expensive, but it is still MUCh more than in N America....
vets are costly here, but there is the SPCA that you can take animals to that are cheaper... not sure if the pills are available in Hk or not...sorry