Radiator replacement

Look up the price of a radiator for your car, add a couple hoses and clamps as well as 2 or 3 gallons of radiator fluid. Labor is probably 1 to 2 hours, but to be fair PT Cruisers have a tall narrow front end and are not easy to get into, so might take a little longer than average. Depending on the cost of the radiator (cheap ones might be $100, better ones might be 150 to 200 range), the price they're quoting you isn't outrageous. Most shops charge $20 per gallon of coolant. You can probably get a lower price by shopping around, or even having a mobile mechanic do the job in your own driveway, but this does assume you can still drive the car around town.