Help Buttercup get proper vet care

Hi, my name's Mercy and I'm a proud owner of 8 guinea pigs. I've had Buttercup for about 4.5 years. I recently noticed that Buttercup's stomach is larger than usual. After an ultrasound, the vet said that there's a lot of fluid in her bladder area. In order to find out whether this is due to some sort of abnormal growth or bladder stones, an X-ray is needed. I'm usually able to afford vet care (in the past I've spent up to £1000 on a guinea pig that had bladder stones) but I'm a student and right now I don't have a total of £178.36 for Buttercup's vet care costs. Guinea pigs' health deteriorates very quickly so she needs to be treated as soon as possible. I'll be thankful for any amount of money as it'll all go towards paying vet bills. I'm asking for £200 as £178.36 is just an estimate and I'd rather have a little bit of money left over incase I need to pay for more check ups or meds. To see more pics and videos of her you can look up my guinea pigs' IG account: @the_cutest_pigs

You can see more pics and videos of her here