Isn't it possible that the MAGAZINE PUBLISHERS themselves are subsidizing these promos in some way? Indirectly, at least.
If most of their revenue comes from advertising (exception: Consumer Reports), they want to pump up the subscription numbers to attract more advertisers and charge them higher ad rates. Perhaps they are almost giving away the mag subs, and therefore, valuemags can actually make some kind of profit?
I think this idea has been mentioned on other threads.
It could also be that ALL THREE levels, i.e., the mag publishers, the Goldpoints program, and Valuemags are trying to get publicity and new customers this way. I know it worked for me. I now pay attention to Goldpoints where I didn't before -- even though I was already a member via Radisson for 3 years or so! And I'll probably do my future mag renewals through Valuemags to get the points (provided I get good service from them this time and they continue to offer points.)
Kathy