I recently re-watched the 2000 film Gladiator, and was reading up on how much of it was historically accurate. One thing that caught my eye in the Wikipedia article was that an early version of the script had gladiators running product endorsement ads. It claims that while this would have been historically accurate, it was removed from the film due to an expectation that audiences would not accept product placements as being historically accurate. Trying to follow the links did not turn up any primary or secondary sources.
So, did this really happen? If so, what were the ads like, and how were they presented to the audience? How much would such ads or endorsements cost relative to, say, a day's worth of food? Which industries relied on advertising? Any other info about how the roman advertising industry worked would also be appreciated.
To add a very brief note to the old comment kindly linked by u/voyeur324:
As I mention in the linked answer, games were sometimes advertised with full-length painted portraits of famous gladiators. We also have literally dozens of mosaics and other artifacts depicting named gladiators. None of this, however, amounts to product placement, since neither the gladiators who appeared in these media nor the masters of the schools in which they trained earned any kind of commission for being so depicted. In Ancient Rome, gladiators sold only one thing: their lives.^(1)
More generally, Roman advertising was - as in most pre-industrial societies - generally more or less limited to painted signs and strategically -stationed hawkers. The best evidence for painted advertisements comes from Pompeii, where several signs for wine shops and taverns survive.