I swear by our baby hammock.
We have a cot but between co-sleeping and the hammock it was only used a handfull of times.
It might take your DS a while to get used to it but if you stick with it he'll probably love it in a week or so.
I used to get a good book and bounce the hammock with a toe while I read and I always amazed at how fast my babies went to sleep. When I had no book it seemed to take much longer lol.