Battery: 1700mAh LiPo (included), CPU: STM32 (max. frequency 72MHz), Charging adapter: 12V / 5V output.
Aliexpress
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Here are coupons that you can use.
Updated:
Banggood
Warehouse in China.
Link: Xiaomi MITU DIY Robot
$154.67 with coupon: BANGGOODSD
Additional Banggood coupons:
1. First page
2. Second page
Price history and price alert
Price history (for all/most countries) for Xiaomi MITU DIY Robot is here. The lowest price was: $69.34.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).