...Haven't used a bought one....
....I downloaded "Amazing Slow-downer":
Amazing Slow Downer
.. and I LOVE it, INCREDIBLY useful, particularly for playing along with a CD track that's too fast for me to play accurately up to speed; you can decrease the speed by percentage, without affecting the pitch...
... of course, the more you slow it down, the more it degrades the sound, but I find it to be no problem down to about 60% of original tempo.
...btw, I'm still using the free Trial version, but I'm gonna buy it for sure.....inexpensive and Hella useful practice tool
