I just got a pair of tall boots.
Tall boots are very, very expensive and very, very hard to break in.
If I were to give my advice I would tell you to wait until your feet stop growing, if they haven't already, and buy the best leather pair you can find. Tall boots can serve you for a very long time... specially leather ones.
You said it was painful getting them on. How so? Was it too tight around the calf, pinching? Was it too tall, poking into your leg? Was it pinching your toes? If so, they may be too large or too small. Usually you experience pain only after you've been walking... and then you'll get blisters.
You NEVER want to spend money: on sale or not, on tall boots that are uncomfortable.
One of my instructors suggested that you poor warm water into them, put your feet in them, and walk around the house for a while. Just wear them. You can also buy softening oils.
As for getting them off: all I can suggest are boot pulls.