Replace blocks or get used hybrid battery

If you can get the junkyard battery with a guarantee and at a decent price, that an entire used pack would probably be the better option. However If you can't get the battery with the ability to return it if it turns out bad, then recondition/rebuilding the battery yourself may be the route to take. Keep in mind you're going to need some specific equipment and tools to tackle a recondition/rebuilding project.

 

or new cells from 'newpriusbatteries.com'

 

if you can get a good deal on a 2016 or newer battery, go for that. But there is no point in putting in another old one.

Changing individual blocks isn't cheaper, but it is more "pay as you go" because you keep having to do it.

Good luck!

 

Neither.
To have a reliable car again, you NEED all new cells in the battery pack.
Which means a new pack or some labor to put new cells in your pack frame.