A bigger consideration might be which antennas require guy lines and ground 
radials.  That greatly affects the space you will need to get the antenna to 
work properly.  What do you want to work?  Which bands do you want to work? 
How wide of a segment do you want to work on each band?  What are your 
antenna options?  If you can build or buy a wire antenna, it's low cost will 
out weigh the cost of an external tuner.
Besides, the longer you shop the more fun you can have.  Once you plunk down 
the money it's all over your decision is made.