A five hour, 3 session checkout process does not seem appropriate for a Cessna 152.  You'll have to look at the savings you hope to gain by doing your flying with the club, and decide whether it is worth it for you to continue.  It would help if your question stated whether or not this lengthy checkout process was specified from the outset-- what was your initial expectation when you decided to check out in the aircraft?  What sort of checkout procedure have other pilots been subjected to?  Since we don't know how you fly, ultimately it is impossible for anyone to say whether or not anything inappropriate is going on.  Maybe the instructor just has a different "style" of flying from you and since you are not really in a position to debate anything, you may just have to adapt even if it does take some time.  As long as you are continuing with the process, you might as well try to learn something useful from the training, even if you don't fully agree with all aspects of your instructor's approach. At any rate, you should discuss your concerns with the club leadership.  If enough people give the same input, some change might happen.

Or find another club.