I couldn't find any of the ST2 ones on eBay for £30, I'd buy a spare set if I could. The ones I found at around £30 are the stick on extensions like the ones
@Mandy sells (for a better price)
The ST2 ones are billet aluminium and CNC'd to shape. They replace the actual switch buttons not stuck on top of the existing buttons. The ST2 replacement paddles go for around £120(ish) when they do come up second hand. They are a bit rare though do to their new cost. I got mine from a member on this forum and I think they are worth it, bit cold in the winter though