Help Save Samsa: Urgent Tumor Treatment Needed

My cat Samsa is only 6 months old and has 2 presumed cancerous tumors/lumps on her belly, under her arm and in front of one of her hind legs. Ive been repeatedly checking these every day and they've both grown more than twice their size in the span of less than a week. Ive been googling the possibilities of these lumps and in my searchings I've only been met with bad news from Samsa only having a few days to be checked out to months left, I am heartbroken and scared by this. My grandmother is the one in custody of me and my siblings, she is on disability and already struggles to support me and my three siblings as is, and I’m currently struggling to be hired as a full time student anywhere as well. I have two autistic twin siblings who adore this cat as much as I do and I don't know if we could take it if she couldn't get the treatment she deserves as I’m struggling with severe depression as is. I found Samsa on a box on the street when she was a baby and she had made my life so much better ever since that day, I want to save my baby and It would mean everything to me if anybody could help in any way.

Jan 26th update: I just received a bill from the vet and theyre expecting around 12k-21k for a biopsy, a scan was done and revealed there is something harmful in the lump in her front chest and the lumps havent gone down at all even after they provided antibiotics, they have only been growing.