Buy 06 Mazda 3 or wait?

Seeing as how im looking to buy my first car, i have been visiting dealers to see some of the Mazda 3's they have that are used. I have about $4200 saved and was looking to save about $5000 before i bought it but something happened.
I found a 2006 Mazda Mazda3 s with 54,000 miles that looked amazing and had everything i wanted for what i thought was going to be $10,000 flat because thats what the dealer said. That would include all the taxes and licenses and everything else. Carfax checks out. Vin checks out. I test drove it and i liked what i saw. Its a really nice car.
But when i went to make sure about the price, the guy said his manager wont approve the $10,000 and the lowest he would go would be $10,500 so about $8900 for the car and the rest on licensing and taxes etc.
This sort of through me for a loop because my whole gameplan was to pay $10,000 flat and pay it off in about 2 years. But now that its $500 more, it would prolong my payments by like 2 months. I have been asking my parents for advice but, they say its up to me and even then im not sure what to do.
So im wondering if i should put the 4200 down and buy it because of how low the mileage is and how good the price is in my opinion or wait another month till i have $5000 and see whats on the market. Honestly i havent found anything close to that low a mileage and its in my price range.
I guess the biggest deal for me is actually making the leap and going for it. Im most afraid of it dying on me and me being in the hole but, when buying a used car thats the case when buying and plus these concerns would be the case in any type of car i would be looking at.
I would certainly appreciate any advice.