What's the weather like in Beijing/KLOC-October? What clothes do you need to wear?
It is windy in autumn in Beijing, and the temperature difference between morning and evening is large. Long sleeves and coats are necessary.
If you are afraid of freezing, it is almost enough to bring an extra thin sweater to Beijing in the middle and late evening.
Anyway, I personally think that the prices in Beijing are not expensive, and the discounts in shopping malls are also very strong. You can buy it anywhere.
If you have time, you must walk around. If you don't have to pay for your own accommodation, the travel cost is quite low, the tickets are not expensive, and the transportation is convenient. Just buy a map and stroll along the subway line.
Down jackets, thermal underwear, coats and so on in the mall in previous years should almost be dumped. Don't be soft when you meet the right one. It's definitely cheaper than Guangzhou.