Depends on many different factors. If your only bill is your $100 rent then to be honest I wouldn't purchase a car for more than 10k just based on your income alone. You make about what I make per year and I made the mistake of buying a car that costs the same amount as my net income. Yes, it was stupid but I learned my lesson. I'm no longer struggling since I got my car refinanced with DCU.
You can try DCU for an approval. You should also try and put down as much as possible as a dp. When I give advice on these issues, I tend to be restrictive. If you think you can afford a more expensive car, say 15k, then go for it. But I recommend 10k or less based solely on your income and what you mentioned in your post.
Make More, Spend Less