I am new to the biking community and had some questions about biking etiquette.

I am currently looking at a bike in the $7500+ range and the though of leaving it outside when I run into a coffee shop leaves me a little worried.
I know I could bring a heavy duty lock (I just dont want to have to carry around a heavy lock) or sit where i could see it but I would feel better if it was with me.
Example scenario - I live 4 miles from whole foods, If I were to ride there, would it be acceptable to roll my bike in while I pick up whatever small item I came for? My bike is cleaner than the shopping carts or many of the whole foods hippies for that matter.
Or a coffee shop same scenario, assuming that there is enough room to roll in without being in the way.

Anyone with any experience on the matter please help me out.

Thanks ahead of time.