There seems to be a good selection of supplements at Poundland at the moment :)
Wassen We Protect Immune Health Zinc and Selenium (£5-10 in Boots) - £1
Efamol Omega (Around £6 normally) - £1
Maximuscle Promax/Prolean (Around £2 each normally) - £1
USN diet Fuel, NRG bars and Maxi Milk are also only £1!