Some trade fairs can be very expensive, especially when you consider all the costs:
Travel costs
Hotel costs
Time costs (time could be better spent working in the office)
Entrance/Registration costs

What is the most expensive trade fair you've been to, and was it worth it (i.e - Did it lead to lots of new business?).

Replying to [ChurchillUK]:
Trade shows are still very essential to all business people.because buyers and sellers are really meet each other, communicate face to face.
As to B2B platform, by the limitations of Technology, many things are still need to improve, such as the internet speed, credit.

Replying to [ChurchillUK]:
Most of the companies investing in trade shows do so for a good reason. It is worth it.
That is why you see companies going to the same show year after year. They have a good idea of the rate of return that has been produced.
If you attend a show with the wrong product focus it will not be
cost effective.

"It is worth it"

Worth what???? My question is how much would you pay, in relation the amount of business you gain as a result!

Replying to [ChurchillUK]:TradeShow is a kind of promotion, you can see trade show as your company's promotion indeed.
So, the question would be " how much you would like to pay for your company's promotion?"
Of course, big promotion means sales up normally.