I have the sort of reaction you're describing around money in general, Liese. Spending money on me is often perceived as 'indulgent'. I bought a 4 year old car when I was a student with some loan money and it was probably the nicest thing I ever owned. I got past the obligatory freaking out about it being too good for me by telling myself I needed something reliable (I had glandular fever / mono) and was too sick to walk to classes.
I crashed it horribly on the motorway less than 8 months later and the insurance company wrote it off - it did its job and saved my life but after that I decided that I didn't deserve nice things. I currently drive a 15 year old Honda. When I took it to the supermarket the other day a guy from a hand wash company offered to wash it. He was Eastern European and probably earned very little and I was feeling like a softie, so I said yes. When I came back, he said to me in broken English. "Your car. Ten years, no wash." Which I found utterly hilarious - because it is practically a skip on wheels and I do not look after it, inside or out. I had just given him a rather filthy car to wash.
Now I think on it, my car is a metaphor for me. I perceive time and money spent on me as not being good use of that time or money. I do shower though, honest. I still have a lot of that shame going on. A lot of it is mitigated by being married to a hedonist. We kind of balance each other out mostly, except when I go off the deep end about unnecessary purchases.
I hope you are able to enjoy your car, Liese. Perhaps I will take a dose of my own advice and give mine a vacuum inside.