I mostly order parts from Rockauto and from forum-friendly dealers. My son has "garage-type" prices at NAPA and (another outlet whose name escapes me right now) but most of the time Rockauto is cheaper for better-quality parts, even with shipping costs are accounted for.
Rockauto actually has one of the best customer service I've ever encountered. I once had missing brake pads for my wife's car - the box was damaged in one corner and the pads probably found the exit, and they shipped me another set for free.
Another time I had to call because of a mistake I made, and ended up chatting with the very nice lady who answered my call.
A couple of times I've had them ship directly to my house in Canada because I wasn't able to get time off to get to the USA, but the shipping costs were horrible - "brokerage fees" were heavy as h*ll. Normally I get the parts shipped to a US warehouse near the border where I can go pick them up.
As for CT.. well, as some said, when engine oil is on sale, but then again... it's still cheaper at Wally World in Plattsburgh or in Vermont... (especially for 0w20).
My 0.02$ (CDN)