1998 Plymouth Breeze loosing Coolant

Hi I have a '98 plymouth breeze and everytime I look under the hood my coolant seems to be really low in the reservoir. There has never been any on the ground under the car so I am unsure where it is going. Oil was changed recently and besides dirty it was fine. I have had the belts, spark plugs and power steering pump replaced in the last year. It also stalls when I accelerate and let go of gas fast. I only paid $750 for it just over a year ago. Is it worth fixing or should I just cut my losses? Thanks Ranita