There are a lot of decent on-line stores out there. I'd like to hear from anyone who knows of bad stores.
I've used Northern Brewer a lot in the past. I don't knock NB because they have been bought by InBev. But I have found they have increased their shipping costs and bulk grain costs such that they have priced themselves out of the market for me since being bought. They do have kits for $19.99 a couple of times a year with low shipping (have to buy 3), which makes it worth it.
More beer for grain (10 lbs and bulk). RiteBrew for many different items. Yakima Valley and Direct Hops for bulk hops. And Label Peelers when they have 40% off sales which they seem to have every few months.
No store has the best price on everything you want. Be prepared to go to several places.
There are quite a few homebrew supply shops in my state or area, but with an online store you have to worry about how up-to-date and current their product stock might be.
My experience is that the on-line stores have a higher turn-over in stock that local stores, and my concern is with how up-to-date and current their product stock might be in the local stores.
Pricing and shipping isn't worth it for me when at least two good brew stores are within driving distances of one hour or less.
An hour is a pretty long distance. When you factor in cost per mile (including initial cost, maintenance and depreciation of your car, which could be as much as 50 cents a mile), the on-line stores could start looking attractive.
My 'local' store is about 15 miles away. Listermann, it is a brewery with a well established store. On-line is cheaper, and when I factor in time and travel cost, (and tax), my 'local' store just can't compete.