Just remember all this when down the road, all the LFS's are out of business because they pay more to purchase the product, they have overhead in terms of staffing, building costs, insurance, utilities etc.
The online stores can send you product stored in low rent warehousing with low utilities, no cost to have display set ups, no extra staff to help you when you have a problem in your tank, and sometimes they don't even have to stock an item as they can have it drop shipped to you.
Now, what are you going to do when you buy a coral online and when you get that electric green whatever, it isn't stunning, but you've bought it? Or, you've received that powder blue you've always wanted but when you get it, it isn't one of the better ones, but, you've already bought it?
To me, the lower cost of online doesn't make up for being able to see before I buy.
I don't want to end up with a lot of corals or fish that I'm not reeeally happy about, but OHHHH, they were cheaper.
That LFS won't survive just selling live stock if everyone buys hardgoods online.
I hear some hobbyists around here saying they are only a few customers compared to the total customer base of that LFS and they can't hurt the operation significantly, but they don't realize that those few can be the difference between just covering costs, and making a living for that LFS.
I buy online for things that my preferred LFS doesn't carry, like my Tahitian Blend, and my 95% spirulina flake food, but that isn't taking money from the LFS when they don't carry it anyway. I have had them order in things for me that they do have access to.
If there is a big difference in the price of something you want, then show the LFS what price you can get it for, and see if he can better his price somewhat. Even if he can't match, but can improve on the price for you, you will help to keep him in business there for the things you DO make use of at their store.
Well, that's my rant for this morning!