I mostly research and shop online.
A majority of the things I purchase ships for free with Amazon Prime.
Of course, this all depends on the on the type of items and the cost savings.
I just bought an 8x10 shed from Amazon @ 51% off MSRP. Free Shipping with Prime (250 Lbs). It will be here next Monday. I bought as bunch of pavers, and some 2x4's from a local Lowes for the base. I wasn't going to save all that much doing that online, and I definitely needed the items before the shed arrived. I wouldn't exactly classify that as an "impulse buy", but more of a "immediate necessity buy". Also, while my local lowes had some nice sheds, they would have sold this exact one closer to MSRP.
As for "regular non-grocery shopping"... we pretty much do it all online. Most of the time, we can wait for the item to ship. And I don't do well (stress-wise) in crowded stores with long lines and jammed parking lots... especially during the holiday season.
Get your games from GOG DAMMIT!