I use my bike for fitness but also have determined that I do not care to wear a kit. A lot of times I may stop at a store etc. and prefer just mountain bike shorts and a T shirt. I have tried the activewear T shirts from Target and others. They are low cost but I find they are not cut for cycling especially if you are tall. Most of the activewear T shirts made for mountain biking are expensive and are in neutral tones so they are not good for on the road. I recently came across some wicking activewear T shirts a Cabelas that are well made in bright colors. Plus they come in tall sizes (these are long enough for cycling) and they do not charge extra the large sizes. Speaking of large sizes, if you need it they come in super size. They are on sale this week if you are interested. I hope they sell a lot of them so they keep them in stock because they work great for cycling.
PS- I have no connection to Cabelas, just like the shirt and thought others would like to know.