A general rule of thumb is that used tools in good to great working order goes for 1/2 the price as it sold for new.......
Given the rust and apparent problems of those tools, I agree with Mike that I wouldn't offer more than $100 and come up to $150 if he balks at that. Assuming I really needed all of them, which I don't currently.
The planer looks to me to be an old WoodTek - low end brand at least, possibly HF - but I could be wrong.