Newbie needs help replacing leaf springs!

Hey all, one of the leafs on my leaf springs has completely split in two so I've got to replace them ASAP. I don't need anything fancy, but I would like to get the best bang for my buck. I've perused RockAuto and General Spring but I'm not sure which is the best. Any recs for a solid spring that doesn't cost a fortune?
Also, will I need to replace both at once so it doesn't ride cockeyed? Pretty sure these are the original springs on my 2003 Tundra 4WD V8 AC, so they could probably stand to be replaced. And do I need to order any extra little parts? A buddy of mine will be doing installation, I just want to make sure I've got everything he'll need.
Thanks in advance!

 

Deaver or Alcan springs is what I would recommend.

The frame and shackle bushings and U bolts should be the only thing you would need other than the springs.

 

This is not a fun project, so don't forget a couple cases of good brew for your buddy!