Usually 1kg of Unflavoured Glutamine Powder is £17.99 + £1.99 delivery.
If you have a Protein Card (please see comment 1 for link) log in to that website (free membership) to get the current 10% off Myprotein code and apply it to your order. Add something else...I added a Myprotein Endurance MixMaster Shaker to my order to avoid the £1 under £10 spend surcharge. So I got the 1kg Glutamine and Shaker bottle for £13.37 (as I used 12 points for a 12p further discount.
So you could get the 1kg Glutamine and shaker for £13.49 making the shaker bottle cost only 71p.
Of course you could add other items instead of the shaker bottle and you don't have to get 1kg as the other sizes are also on special today.
Check out the other products as there seems to be some good discounts on other supplements too.