If you want a non-standard configuration (which, laughingly, includes SSD models), the only options are from Apple directly (new or refurb), or from a Authorized Reseller or Specialist.
Discounts via Apple are pretty clear -- buy refurb, on Black Friday, or from one of the special stores they set up for Education, Government, or an EPP set up with various companies. Many tend to overlook the latter; store qualifications are easy to meet, and there's a good chance you may know someone who qualifies. In any case, discounts will be modest -- 10-15%, but it's something.
The big Apple retailers do also discount modestly, but they don't carry non-standard configurations. For those, one must go to an AR or Specialist, but the good news is that some of them do discount. Keep an eye on the other big rumor site, which often runs deals through Adorama or B&H, and won't collect sales tax from the majority of states. That last part alone can make up a large part of the difference between buying directly from Apple or a mail order dealer.
