Did you check anyone or any site prior to your asking??? Or are you asking all of us to do all the work you should have??
If you checked whom did you ?? and what fare did you find?? Its not considered proper edict to simply ask for something unless you yourself have done some homework regarding it 1st. Once youve done that then come back and post the cheapest you found and ask if theres a way to get it cheaper.
When you check that means checking a few airports on both ends = NY check LGA,JFK,EWR for DTW = DTW,FNY,TOL,CAK (ok its a 3 - 3 1/2 hr drive but if its cheap why not). Before jumping on the tkt check car rental rates as whats cheapest for a flight might not be for a car
yep alittle work is involved as you can see besides simply posting "Find me a deal"
BTW at least you put down the dates but you didnt put down if you would leave a day before from NY or a day later from DTW