Good source for printer ink/toner?
The ink for my printer costs an arm and a leg. It's a Canon Pixma model MP530. I have been buying the refurbished cartridges at Staples and it's still expensive. What really annoys me is that the printer won't print once one cartridge runs out. For instance, I want to print some letters in black ink at the moment, but the magenta cartridge has run out so it won't print anything at all.
Has anyone found a good source for ink cartridges? I get those spam emails all the time offering great bargains, but I don't think I will rely on that.