I started to do that at AWS. You basically cannot get a 64GB memory machine. I can't remember if I actually got one configured but I do remember calculating that a 6 CPU 64GB machine with 250+ disk space would run about $75/day. That would be in addition to a machine running PRIME. So for 3 months of lab you could just spend $6K on hardware and run both APIC-EM and prime on a host (like ESXi).
APIC-EM will run (not sure how well) on 40GB but as I remember the best machine I could get at AWS was 32GB
Good luck and let us know what you find.
Your Cisco SE should be able to give you access to dcloud.cisco.com where there are various APIC-EM labs you could demo if that would work for you. You just could not manage your own gear but still get the feel for it.