A really good article to read which can save you money is from the Guardian by Hilary Osborne which you can read here.

This is a summary of her list;

1) Buy your food in bulk and online

2) When buying an animal consider a mongrel as it is cheaper than a pedigree

3/4) Do not rush to go to the vet for minor ailments, however keep jabs up to date

5) Like number 1 buy your pet medication online

6/7) Buy pet insurance and make sure you shop around for it

When on holiday use a pet sitter or form a pet sitting group to look after your pet rather than use a kennel or cattery.

9) Buy toys and bedding from a charity shop

10) Have your pet spayed/neutered

Also Hilary could have suggested using a pet shopping price comparison like ours where you can compare prices from ten online pet shops to save money and a lot of time.