Why does my cat keep peeing on the bed?

One of my cats keeps peeing in the same exact spot on my bed once or twice a week. She has been doing it ever since I moved back into my mom's house about two months ago. I brought my other two cats with me and my mom's cats usually hang out everywhere else in the house (she gets along with my cats but hisses at the others). I leave my door open so she can come and go if she wants, but she usually just stays in my room. She otherwise goes in the litter box just fine which I clean every 2-3 days. I don't have the money right now to bring her into the vet to make sure it's not a bladder problem or whatever, so what else might it be? I've heard cats will go to the bathroom on things if they are mad at their owner or uncomfortable or stressed out or something, and I'm hoping that's all it is.

you probably smell good