New Scientist Magazine Subscription 10 Weeks for $20
Usually $8.74 per issue for print & digital or $6.74 per issue for print only (in a six month subscription). I think to buy it in the newsagent it's around $10 from memory.
For ten weeks only, but since you can set your subscription in the future you could probably buy several and stagger them to get a continuous super cheap subscription. If anyone manages to do that, please share!
I'm not sure when the promotion ends but I know it will - took advantage of a similar offer year before last as a gift.