Cheapest cat flea and worming help please

randm

Some has asked this question in an old thread, I need to update it as the posts are a year old. We have given a home to an ex ferral cat, we took her to the vet today for her second lot of injections and ended up coming home having paid £43.30 for a pack of six advocate and £3.37 for one drontal tablet. We have only had her 2 weeks and my husband is having a virtual heart attack ! Is the cheaper way to do this by getting a prescription and getting it on line, one thread said you don't need a prescription for advocate. Is this true? Can someone update me with the best worm treatment and flea treatment to get and perhaps any websites etc. I only asked at the vet for the worm and flea treatment because the cat charity lady said don't buy the stuff in the pet shops as it doesn't work. But to buy it at the vets.
Can you believe they also charged me £14.72 for a 3G tube of antibiotic eye cream.
All advice gratefully received , never had a cat before. Only guinea pigs!,,,