I understand the convenience of wanting to order everything at once, but you are also dealing with the fact that usually places that specialize in something have a better selection (and often better quality) of that "thing" than places that try to offer a little bit of everything. So I too would suggest breaking up your order. Plus it has been my experience that places that sell a little bit of everything tend to really overprice their "everything."
For plants and fish, I would first recommend you check with a local aquarium club...often at monthly meetings they have auctions where you can get things for next to nothing, or even for free. I just recently set up a couple tanks and someone from our local club had recently done a bunch of trimming/thinning in his planted tanks, he gave me a massive bagful of his plants for free. If I had bought that amount of plants online or in a store, it probably would have cost me $150 easily. Plus, when you get plants or fish from someone locally who is an aquarium enthusiast, you are just about guaranteed they will be in much better shape and they won't have been exposed to the added stress of shipping (more significant for fish than plants, obviously).
Your second best option is to check the classifieds section (or buy/sell/trade) section of websites like this one. Again, you have hobbyists who are dedicated who are often selling extras out of their tanks. The Aquatic Plant Central forums are a great source for plants. You can often find both plants and fish from this site, as well as petfish.net and fishforums.com.
Your third best option is to buy things from
Aquabid, essentially "ebay for the aquarium hobby." You can often get things there that you can't find anywhere else online, and in general I have found the sellers to be professional and the quality of everything to be very high.
If you absolutely *must* buy from a store, then a few I have either used myself or heard good things about would be...
For Plants
Sweet Aquatics
Aqua Botanics Store
For Driftwood
Florida Driftwood
Manzita Burleworks
For Fish
Live Aquaria
That Pet Place
Good luck!
