I try to always buy local when I can. I will NEVER shop at Wal-Mart. It would have to be the LAST place available for me. Same with other big box stores. I prefer little local hardware stores, etc. I do order online stuff though too, just for selection I can't get here. I have my local pet food store order Rocket's food though even though I could myself, because I really like them and I want to support them.
This hits home to me because in my work season, I can't tell you how many times people come in with (or without) a sample of a plant or an issue, I show them their options for treatment, etc, spend 20 minutes explaining how it got there/what's going on and how to use the chemical/fertilizer/whatever and then they put it back on the shelf and say "I can get that cheaper at WM or Home Depot" and leave.
$%&#$ THEN GO ASK THEM HOW TO USE IT. And suffer the consequences.