I have yet to get an ad with ChatGPT, I think it only gives ads when you are asking about consumerist type things, which I never do but seems a completely reasonable thing to me and I would not have issue with it giving me ads if I were to ask it about which ketchup is best or even how to make ketchup. As an incompetent programmer, Claude has not worked well for me and ChatGPT has never given me ads when asking programming questions.