[help] Where can I buy a BIG Kara from online?

I have seen some Kara that are 500g or more. I would love to get my hands on one/two of these.

I'm a big guy with a few muscles and I barely notice the 250g one that I already wear.

The only thing is that I don't want to pay the extortionate prices you find on some websites. Not because I'm cheap but A) if it's expensive it become a bit of a showy item and that kinda goes against the whole "pride" thing we sikh are supposed to avoid. B) it's a lump of rolled steel/iron. There is about £20 of material and man-hours in there. why charge £150? that's greedy! C) I'm on disability benefits and can't afford a MASSIVE cost.

So... any ideas where I can look?