Depends on what you want.  I find Fosters is too expensive for my tastes,
then again so is Petco and Petsmart.  There is a site called JB Pets
(www.jbpet.com) is reasonable, and Marilyn in customer service is wonderful
(very helpful, curteous - a rare find in custmer service now of days).  Only
problem is most of their products are for the dog owner, they do have cat
products but limited.  I honestly can't remember what the s&h was, but the
order was express shipped at no extra charge)

If you are looking for flea things, such as Advantage, I found a great buyer
on ebay, he beats anything I've found on the web (I think he goes by
best_cents), and shipping is quick.  It's the real product and not a
knock-off.

If anyone knows where I can buy inexpensive cat toys I'd like to know!