you say under $300/month which is cool, but you left out what you have for a down payment, length of loan, and your credit. That will help define a real budget.
I financed about $20k and my payments are $351/month over 5 years @ 2.09% which comes out to roughly $17.50 per month per $1,000 financed, was 28/homeowner/excellent credit. those numbers could give you a direction on estimated budget