Honda Fit, called "Jazz" in Europe.
Probably the most practical supermini you can get (and I'm a Mazda guy:-)). It's people-mover style body allows for great variability, it's spacious and it's also good to drive. Yaris is way too small.
Pontiac Vibe is, however, a one size bigger then the other two. The closest Vibe rival is Toyota Matrix.
You may also try a Mazda3 hatch, it's better to drive than all of the cars you've mentioned, it's more reliable (
https://tuvamerica.com/tuvnews/hotnews/p… and with the rear seats folded, you get a very spacious wagon. (Personally tested in IKEA shopping :-) )
If price and insurance are the issues, you'd be best off with a Honda Fit as with these criteria its probably the best overal package in the supermini segment.