yup.....togoparts.com is a good one to start your search. you
can actually advertise a WTB post. you may get lucky.
a few weeks ago, a chap from bishan advertise to give away his 2
bikes for free. i am not sure got takers or not.
you may want to give it a shot, go to marketplace, click
complete bikes and scroll to like maybe 8-10 pages down to look for
it.
Another option is actually carrefour. on weekends, they
advertise really cheap bikes, you can get entry level mtb for like
$50-70. but you risk kena stolen (again)