Just been checking out short-sleeve cycling jersey prices and they seem more expensive than similar quality running jerseys. Any reason not to use a running jersey? I don’t need pockets, just a slim fit and good wicking.

cycling jerseys tend to have longer backs – you might find you end up with a gap twixt shorts and top when you lean forward.

As above, running tops may well be too short when in your riding position.

Wear what you want, as long as it’s comfortable. But as above – short back and neck might be a bit wide.

football shirts can usually be found quite cheap

MandM

Hmm ok, that’s a pain. The cycling jerseys at my LBS are all £35-40 if you want one that doesn’t look terrible. Seems a lot to pay for a polyester t-shirt…

you can get them cheaper than that if you shop around
fox jersey at stif

Rugby shirts are always a good bet – vary in thickness and you can get long or short sleave. You can pick last seasons club shirts up for about £20 a pop and they’re generally wicking but hardwearing technical fabrics.
Try Lovell Rugby

they’re not that short. i find my ruinning tops just touch the top of my shorts will riding – ok in the heat but not much cop in the cold, the lack of a neck and a zip mean s temp control is not achievable.

also lack of pockets sometimes is an issue.