I got mine off Amazon.com too. The free shipping on prime and no tax makes a big difference on $100+ and very heavy items like this.
What is your budget?
In general, the taller the better, but tall ones can be tip prone for cats that like to leap off them and race up and down, so might need to be braced on one side against a wall, or put a 45lb weight disk (if you have a workout bench) on the base.
Also of note that you don't HAVE to use a cat tree for a climbing surface. You can adapt various furniture, or use shelves (just need a stud finder and a little carpet tape and non-loop carpet for grip).