Serial to USB in DIY duino

I'd like to move my project from breadboard to something more pro, but while I know how to make microcontroller to work standalone, in this project (simple lcd display with programmers api to display data from games on it) I need usb-serial connection, and power via usb when we're at it.
How should I do it? I can't find tutorials about diy arduino with usb to serial.
Or maybe I should just order handful of cheap usb to serial converters off China? (but can I use it to power my project as well?)

Available in 3.3V and 5.0V

Build this into your card, <$9

Examples: (with round machine pins, plugged into a socket)

So what I need is USB to UART module? Thanks a lot!