You can get running t-shirts and long sleeve tops cheap if you look around. They work fine for commuting and you can wear them off the bike.
I tried going this route, but normal active wear t-shirts don't have the rear pockets to store my cell phone and snacks. These are also cheaper than the t-shirts I see at bob's or kohls.
And who bought the last blue medium jersey? I just got an e-mailing saying they were out after I ordered them.