If you go to a reasonably priced school or FBO, it is cheaper to do your training all at once. First, prices aren't going to go down. Second, the more often you fly, the more info you retain and the less you have to be re-introduced to. As far as repayment, do a web search. I paid as I went but was still able to do it all at once. A good school I attended:
www.prairieairservice.com, MUCH less expensive than ATP and you won't be receiving your instruction from a low time MEI.