You can get the complete rocker assembly (rocker arms, shafts, springs, retainers, bolts, everything) from our Ford dealer forum vendors for about $80-90 each (need one for each side), and pushrods are about $5/ea.
I like the Ford parts since they are known quality and Made in Germany like the originals.
That said, getting a set of 12 Sealed Power rockers for slightly under $100 isn't bad if the savings make a difference. The rockers aren't too hard to take apart and put together, but you need to be careful when removing the retaining pins and springs at the ends so they don't get messed up.
I would avoid anything from Delta, they refurb/fill in used rockers, and thats just not an acceptable fix for these products, as the experience of other forum members has shown.