Why would you pay full price for a new cartridge when neither you or your printer can tell the difference? You save roughly roughly 50% using Cartridge World's refilled ink cartridges vs. buying new. CW encourages you to come in to their store by charging (something like) an additional $2 if you do not give them your old cartridge (which they refill and resale). As such, CW does not provide the ability to order their cartridges online. However, you can bring in your old cartridge for credit even after you've purchased their ""new"" one. Additionally, my experience has been that they will replace one of their cartridges that you may be having trouble with no hassle (and as it turned out, the problem was not their cartridge).
Pros: Savings on cartridges...
Cons: ...but no online/mailorder service.