HC-06: Dealextreme $5.50, Banggood $5.99, Gearbest $6.57, Aliexpress $2.58
Arduino Nano v3.0: Dealextreme $3.46, Banggood $2.77, Gearbest $4.27, Aliexpress $1.66
Ebay has a pretty good return/refund policy. And then you can fall-back on Paypal too.
Anecdotal evidence, but I have had far more success with AliExpress' dispute/buyer protection system than eBay's.
eBay is laughably bad at disputes. I have received several items from eBay which were DOA, and my options were to take a very reduced refund, or ship the item back to the seller at my expense.
Same issue with AliExpress, upload evidence (pictures/video) of the DOA item, full refund no further questions.
PayPal is another nightmare in of itself.
The thing is, on Aliexpress there are many, many sellers of each of those items and there is often a significant price difference among them. If that is due to quality or delivery times I have not figured it out yet. So I usually buy from the cheapest who has a fair number of sales and few if any complaints in the reviews.
KY-008 laser transmitter module $0.32
5V stepper motor with driver board $1.82
LCD1602 I2C board $1.68
4X3 membrane switch keypad $0.52
STM32F103C8T6 dev board $1.58
K975 Micro 130 Vibration Motor (2 pcs) $1.48
Tilt sensor module $0.37
KY-013 temp sensor module $0.29
GY-521 gyro/accel module $0.99
WS2812 RGB LED 12 bit ring $1.40
RF receiver & transmitter module pair $0.82
IR obstacle avoidance sensor module $0.69
HC-SR502 PIR motion sensor module $0.72