Non-linear g29 spring

[Banana4Life]

Hello, I would like to find a non linear spring, to give a better feel to the pedal. I know some places like GTEYE and NIXM, but these are around $30/40, possibly more after shipping. I was wondering if you could get them somewhere else for much cheaper, somewhere from B&Q or somewhere like that. Attached is picture of linear vs non linear. Maybe even stronger spring would do? Thanks