I just went though this.
I had a couple long sleeved, loose, wicking workout shirts I bought from walmart for about $15 to wear to the gym in the winter. I tried one fishing one day and loved it, it's worked great.
So I went to walmart and they no longer had them because they had moved on to summer clothes.
So, I found a couple Redington shirts at a local fly shop for $34. THey are great also and better priced than any of the other brand name performance fishing shirts you will find.
A few weeks later I was at Target and found that they had similar shirts on close out (left over from winter) for $11.
So basically. for the best deal on good shirts you can either wait till winter, or buy some Redington Lost River shirts.