Cost of each reuseable cartridiges is between $0.50 to $1.00 each, depending on the quality and the number of cartridges you buy.
What is the difference between the free ones mention above and these reuseable one are:
Easier to remove the end-caps.
Secure end-caps once it latched on properly.
Generic color; like gray, black, etc and some space on the cartridge to label.
I used to print all those PlusX, TMX400, NPS, EPL, etc labels and put them on after loading. Or if you use single type of film all the time, then write in on the cartridge using a permanent maker.
I tried those "free" ones; I find that though it is easy to pop the end-caps using a "bottle-opener" type of opener, it is harder to keep them on. Once I drop a box of rolled film, the resuseable cartridge' end-cap stays on while some of the "free" ones end-caps popped out ruining my film.
If you don't mind all the "different" color, type, ASA, on those free cartridges, I guess its OK. However, I find that my black reuseable cartridges kept the ASA on the film camera consistent. When shooting fast, it matters alot.
YMMV
Where to find in Singapore? I don't know. I bought my when I was in the US. Anyone else can help??
BTW, I am selling my bulk rolled films in those reuseable cartridges. So if you are looking for these cartridge and would like to try some of the film. I am using digital now, so I have already sold the bulk roller. These are the film I am getting rid of.
http://forums.clubsnap.org/showthread.php?t=137426