I grew up in the 60's and early 70's with a family of 3 girls and 1 boy. Mid income, 98% of my clothes were homemade, by the time I was in 4-H (bleed green still) and at 7years I was sewing my own clothes and by 13years I was sewing for others. Always used what mom could afford for us. By the time I was 21, I was DWF with 3 babies, then again it was what I could afford (used toilet paper for Kleenex - how many of you remember those days?)and made most of their clothes till the graduated and moved - now just gifts.
Now that I am a very proud grammie to 6 precious grandchildren(make them each summer clothes each year so far), I still buy on sale, but my luxries include having not one, but two pair of ginghars, my fabric varies from Walmart - LQS - Online (find what I need to go with I am working on.) and Kleenix with Lotion and a box in almost everyroom in the house and every vehicle I own (no kids at home).
Yes, sometimes, I will purchase something now, just to try, if I like it, I keep, if not I Play it Forward.
I still won't buy my DH a store bought western shirt, because I promised to make him ONE for every month since we go married (they are cheaper that way, and he thinks he is "special" in that way - have a wife that sews).
About 5 years ago, I purchased duplicates of guilting tools (rulers, rotary cutter etc...), just so I don't have to repack something to teach a class or take one.
As long as it works, I will wither buy store brand or big name brand if on sale.