Transponder keys for 1997 Oldsmobile Achieva

I have a 1997 Oldsmobile Achieva. For the first year and a half I have been driving my car with a duplicate key (It doesn’t have the black cover on it nor a chip). I had an alarm and a remote starter installed a year ago but now the car won’t start. I had the alarm and remote starter taken off but the car still won’t start. Then the person asked me about the orginal key. I told him that i never had the orginal key to the car. The person who sold me the car only gave me the duplicates (which I didn’t know at the time). How much would a transponder key cost and if I was to buy a blank key online that could be programmed would that save me money?