I do not own any pilot shirts - I fly in a cotton polo-neck and usually either a Nomex suit or a Nomex or leather jacket.
If I feel the need to wear gold bars, which happens about every third year, and then only briefly, I put them on a jacket or my flying suit.
If I did need to start wearing a white/eppauletted shirt, which has not happened yet and I suspect strongly never will, I'd get them made by my tailor in Bankok. A quick look at their website suggests I'd pay about £25 each.
No way would I buy the polyester-heavy shirts sold by any UK pilot shops, for all the reasons already said. Uncomfortable, and dangerous.
G