Well, I'll be honest and say I found the TE a huge time saver. Dolciani is heavy on word problems - the C level, and even some of the B level ones, can be genuinely challenging. For the non word problems, I didn't need it per se, but it sure made it quicker to check work. Sure, some of it could be done on a calculator or in my head, but there were a lot of multi-step problems in there. Not hard, but time consuming enough that it was worth the money for the TE. Plus the TE wasn't *that* hard to find or that expensive. I think I got mine for like $50 or so and it was in pristine condition. I've seen them be much cheaper than that too. Unless you need it right this minute, I think you can find that sort of a deal by looking every couple of weeks for a couple of months. Just be patient. They pop up. Also, my editions didn't match exactly and it wasn't a problem.
That said, the teaching notes and other info in there is super minimal. And there are no solutions, just answers, so you do have to be able to understand it to explain the problems. It's mostly just a convenience, not a key teaching resource.
I agree with the pp's that you definitely cannot have a student do Dolciani from the TE. The answers are right next to the problems and there's no way to mask them easily.
ETA: No super cheap deals at the moment, but I did see this TE for under $70. With the text at about $25, that's still around $100 for pre-algebra for the year, which, honestly, seems like a reasonable amount to spend, especially since the resell value won't drop much on those if you're nice to them.
Edited by Farrar, 06 January 2018 - 08:18 PM.