@tatel AND mwb1100
I think it is not the taxes but the importers. they sell with as much profit as they want. then the retailers are the same. none of them will take responsibility of a possible faulty product easily after selling the product most of the time unless you buy from internet website which has somewhat better support. iran is a sh*t and corrupt country. everyone can break the law easily with money. so you need to buy very cautiously. manytimes, you may buy a product for tmore than two times the price on aliexpress or any other reference. you can find good deals too, specially on things like phone chargers and cables when there is a lot more competition but in the realm of oscilloscopes, it is a complete joke and mess with very few options available .i wish i could measure the noise with my sound card, it would have 24 bit resolution ,way higher than most of the oscilloscopes. i know i should be able to measure the main's ripple and it's harmonics(50hz and up) but the damn SMPS noise is gonna be at different high frequency bands. finding an oscilloscope is a must if i want to it right.