Is there a big difference by booking from a local Supplier? And do I save money? How much?

Yes, usually you will most likely to save minimum 10% to 15% to maximum 30% to even 50%.

Check the links below

https://www.rezdy.com/blog/how-much-commission-should-tour-operators-give-agents-for-bookings/

https://en.wikipedia.org/wiki/Travel_agency)

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