It would be really nice if anybody could show me any good external disc drives for MacBookPro under 40$
Are you looking for a bare drive, or an enclosure and drive?
My $.02 is you may be hard pressed to find any drive/enclosure at that price point. A bare drive will be probably be tiny, unless you buy it used.
Check out ebay, for such deals
I am looking for a enclosure and drive
such as the http://www.samsung.com/au/consumer/pc-peripherals/optical-disc-drive/dvd-rw/SE-208DB/TSBS#none
is that a good one