Vitamin C - can quality vary?

I'm taking high dose vitamin C in powder form but am rather disappointed that the drum didn't last that long.

Need to restock and am wondering about tablets - is all vitamin C equal? Can it vary in quality/potency?

Any recommendations of where to buy at cheap prices?

Thanks!

[helvella Administrator Thyroid UK]

I have posted this link several times - it says about where we buy our supplements:

dl.dropbox.com/u/318411/Whe...

Very often they have been less expensive even with shipping, etc.

Rod