@Granrey, sorry to hear about your poor experiences. Hopefully the 3rd one will work out.
I have 2 local retailers -- one is good as gold, the other insulted me 2 years ago and I haven't been back.
I buy locally as much as possible, so my good retailer will still be there next time I need him. I buy online when it's a specialty item he can't easily get (like an enzyme) or the price break for buying online is large enough that I have to think of my own wallet first.
Shipping weight is a problem when buying online. Light things are not often a problem, although the S&H when buying directly from a manufacturer is typically high. I found kits are expensive due to weight, and since my local shop will order anything I want (assuming it's available) to I buy kits locally.