hairy1:
I got this one. It won't add much at all to the build price I wouldn't imagine. About $11.
The momentary press one is really nice but is about $50 so not an option. That is designed for their smart home stuff:
https://www.pdl.co.nz/products/detail?CatNo=PDL356PBSS&tab-document-1=0&itemno=PDL356PBSS-VW
For the PDL 600 series PDL MOMENTARY PUSH BUTTON MODULE 10AMP 24VDC/250VAC