Hello SAMO ;-),
-driver seat(cracking,banging.....),how to solve?
Unfortunately I do not know the details, usually they replace some bearings or rolls. My Ignis is not affected by this problem yet, but the seat construction is not rocket science, any garage should manage to fix it.
-air cabin filter(my local official service said that that is too expensive to change it(39eur)wtf?????,so i have a hole instead air cabin filter.
Ignis is sold without a filter but fortunately is fully prepared for one - jsut need to plug it in.
You can try to get one from Opel Agila, probably also a cabin filter from Opel Corsa would fit but I'm not sure. In Poland a couple of aftermarket filters are available, price is not more than 20EUR. And it's really easy to change it.
-i dont trust official service(i wish that i have been there at the spot,when the serviced)
Official service can handle only regular maintenance, anything special which is not on their checklist is usually too much for them. ALthough tehre are exceptions, as usual ;-).
-from now on i will do it myself so:-what kind of oil to change
Recommended to use the same as before, semi-synthetic 10w40 should be just fine, if you want to invest some more money you can go for full synthetic oil.
-brake pads and disc
Lots of replacement parts available much cheaper than original Suzuki spare parts.
I myself use ATE (Contiteves) discs and pads, but you can also get ones from Bosch, Delphi, Textar, Ferodo, Brembo and other manufacturers.
Hope it helps,