You have just 20 minutes in a new yarn shop and a tight budget - it's sweet torture! If you had big funds, you could just grab and run and sort it out later. But with little money to spend, you need to shop carefully, only there's no time for that!
I had decided ahead of time on fingering weight but that only helped somewhat. I finally settled on Schaefer Anne - but even then with so many colors I could have taken twice as long as I had. I settled on one that matched the dress I was wearing.
The yarn looks much different in a ball - the color actually chnages ever inch or so. That means it will blend together into a truly verigated item. Or, I might be able to try a pooling effect, as in this shawl.
What do you do when you have to shop fast?