Volunteering means giving your time and skills of your own free will and for free, as I understand the word. If you expect to be paid, you are not really a volunteer.
I'm not sure whether I would volunteer to work for the Olympics - I have a feeling that much of the work may be quite boring, and I'm not personally sure that holding the Olympics is going to be a good thing for London (or the rest of the UK) - but if I did it would be on the basis of unpaid help in whatever way, not recompense to me nor the opportunity to purchase a Russian* doll with the Windsor clan dressed in athletics gear, or whatever the marketing people/tat merchants dream up.
The Moscow olympics 1980 are one of the few that seem to have left a lasting (30 years!) legacy of symbols and souvenirs. What this says about capitalism, socialism and marketitng, if anything, I'm not sure.