The only difference between buying through a reputable site that's an official dealer VS a LDS
is that you can try the equipment right away before buying at the LDS.
I understand the urge to save money by buying on the internet.
It's really your choice. I'm sure the LDS understands your need to save money.
Now if you continually buy everything online then that's a different story.
If you want to support your LDS then support it. How you do that is up to you.
Me personally, I chose to sacrifice about $200 to buy all my hard equipment from the LDS.
Now even though I tried on different styles and sizes of BC, I got a BC they don't carry in stock, and it was too big.
Did a pool dive with it and decided out I didn't like it (inflator leak and a bit too big).
They talked to the manufacturer and I got the smaller size.
Then the manufacture botched my octo integrated inflator and my integrated weight pockets.
4weeks and two shippings later I got my BC back.
I don't wanna tell you how I would have felt had this been an online dealer.
Long story short $500 is a great savings. If you wanna support your LDS but save money as well, I would just buy small things from them
ie. save a dive kits, snorkels, clips, retractors, slates etc.
Taking classes from them makes them happy as well ;D