I’ve a basic park tools wheel truing stand and as all my wheels are thru axle now I would like some proper way* of using it with 20mm, 15mm and 12mm thru-axle wheels. Park tools do an adapter but it’s in the “how much!” category –
https://www.leisurelakesbikes.com/18047/products/park-tool-ts-ta-thru-axle-adaptor.aspx
Before I bite the bullet does anyone know if there are similar but cheaper alternatives? Google suggests either some alloy insert things made in the US for about £30, or the park tools TS2TA adaptors which I don’t think will work with my stand.

Just stick a QR through the hole where the axle goes and do it as normal.

Hmm – cheap, I like it. But how will I make sure the QR is centered?

These work fine;

http://www.chainreactioncycles.com/park-tool-thru-axle-adaptors-ts2ta/rp-prod58539?

They clamp in the ‘dropouts’ in the stand and have a convex bit on the other stand that holds 15/20mm end caps in place and level.

But how will I make sure the QR is centered?

doesn’t matter, so long as the wheel spins freely.
you check dish with a dishing stick, not on the stand. 😉

Or just flip the wheel in the stand.