You can piece rods online for a lot cheaper than companies like SPL. For example, the thread on NRR.

I made tension rods and toe rods/traction rods for about $80 a pair and used the same rod ends and aluminum rods just like SPL tension rods.

I have had multiple pairs of SPL rods, and on two pairs of tension rods my rod ends rusted and SPL advised me they were not safe for continued use.