What are you looking for?
Salt, heavier items, etc:
Dr. F&S...they have a flat rate shipping and cheap prices to start. With that much weight, shipping is usually off the chart.
Lighting:
hellolights...no oversized charges on things marinedepot charges extra for(reflectors, bulbs, etc) MD is great for having no shipping charge, but get a 36" vho reflector and its $6 oversized charge, 48" is $15 oversized charge. Got items cheaper and larger quantities for less shipping after the extra charges.
Other equipment:
Just find the best priced place from a couple search engines...if it's products that can't really be screwed up and as long as a company stands behind guarantees of arrivals
Livestock:
Oh, so many choices. Here are some I've ordered from and my experience so far.
Extremecorals...my latest shipment. The item did not survive within their guarantee(I think it's 10 day). They credited me even before the whole colony became toasted. All they asked for was a picture. Great products, stands behind their word...a little pricey, but worth it.
That pet place...Good cleaner prices, quality products.
Makin waves...Great customer service. Some of their products are priced better than I can find anywhere else. Purchased fragile, known animals to be poor shippers from them and most survivied the 2-day shipping(have since changed from DHL...bad shippers). They actually have to replace a couple DOA's for me, so if anyone needs anything from them also, I can get it, but it may be a while until I get those items.
I've heard good things about a lot of other online companies and have used a bunch of others for certain items as I needed them. I may come up with more that I can remember later and will try to add to the list