Luna's Limp

My Luna is limping... A very odd, sometime limp. She is favoring her front left paw, and I'm not sure what's going on. It started while I was gone in the hospital or under so much meds I didn't notice. So, I'm whisking her off to the vet, and Jake's afraid I'll be spending a ridiculous amount of money. So am I, frankly. But I can't tell if she's just hurt herself a little or if there's something BAD going on. So, off to the vet we go.