I don't know any trainers that call their clients to set up lessons, it's the other way around. Now if my trainer has a completely empty schedule and gets desperate, THEN she'll call me but that's happened maybe twice? But that's only because all her clients were sidelined with either injuries to themselves or their horses and since my horse was down with an abscess... I wasn't riding either!
I don't know how large your budget is but around here a decently trainer horse with some Dressage training isn't going to sell for less than $5k. My trainer waived all her fees when she helped me buy my horse so that I could afford a more expensive one but she only did that because I was boarding multiple horses with her, had training and lessons on an on-going basis with her AND she had some upcoming trips planned and I agreed to do all the feeding/cleaning while she was away.