The Wemos D1 mini is a great board to start working with the ESP-8266 chip. It does not only contain the chip and basic resistors, it includes a micro USB port for flashing and power supply, both 5V and 3.3V pins for usage with other connected hardware, an CH340 USB to TTL converter, a reset switch, and all the pins in 2.54mm raster so that it can easily be used on a breadboard. Another big advantage is that you can get shield boards with different types of sensors and actors for quick hardware solutions. If you buy it directly in China, it is unbeatably cheap.
Find more details about the board and companion hardware at https://www.wemos.cc/
This is the pinout, including the names used by NodeMCU firmware