I'm using a K&N on my 2410 but it costs more, not less. I crossed the Kubota part number to another brand- can't remember if it was Purolator or Fram before crossing that to K&N.
Tractorsmart has always had a flat shipping fee per order, so if you need a few things, that would be the way to go.
If you want the K&N filter number, I can post that later.