handheld oscilloscope for repair motherboard...?

Pretty useless for PC repair IMHO. A simple POST tester provides more information.

Although there is very likely to be lots of very competent people here, all of your questions would be more appropriately asked of the vendor, not to a news group.

However, since you asked, here are my opinions: Yes, the quoted prices are in US dollars. The prices for similar items are the same because the effort and techniques needed to calibrate them are approximately the same, therefore, they charge the same price. The shipping cost will have to be quoted by the vendor. Only you can answer the question about the calibration data requirement. If you are going to use the equipment to calibrate other equipment, then you need to maintain the calibration data for all the equipment that you use for calibration and certification.

Which one you choose is your decision, and yours alone.

Cheers!!