Some vendors start providing discount at 3+ or 5+. (Farnell Electronics, for example.)
EDIT:
Still going to work out to over R3000 for 8 Raspis. Might need to look at a Chinese knockoff, or any cheap alternative that can run Python and be networked to form a small cluster.
Your probably better off getting it from China via Aliexpress, but expect it to take several months to ship to you.
RS is making a HUGE profit on them especially the RPi A+ , funny enough you would think RS is cheaper, but you pay less to buy a Pi that's been shipped from the UK to China, then back to South Africa.