The wireless card is 50GBP+VAT and the board it plugs in to is 20. thats > $150 to control an LED wirelessly which is only a little bit insane.
I'd love to throw together little 'internet of things' projects here there and everywhere but the per-unit cost just doesn't allow it.
So, what you need is a machine that has WiFi connectivity plus GPIO plus a few components. I'd suggest that you can do this with a Raspberry Pi plus a small WiFi adapter.
Using Amazon.co.uk pricing:
Raspberry Pi Model B: £42.89
Raspberry Pi Power Supply: £3.95
Edimax WiFi Adapter: £8.15
Some LEDs + resistors (est.) £2.00
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£56.99
And the Pi has a lot of power to do other stuff. I have other ambient stuff in my house running off a single Raspberry Pi plus it's doing CCTV motion detection as well.
https://www.sparkfun.com/products/10822
It's a low-power WiFi client with a bunch of IO that you can configure to periodically do a TCP call to some server you own to get orders on what to do. If you don't mind having it always on you can invert that and have the server initiate the call. You lose the ultra-low power usage in that case. I've been evaluating it to create sensor/actuator networks and it's been great so far. It also has a serial port so your display example would work as well.
It's amazing that a full computer (the raspberrypi) can come so close to this on price but the raspberry is an energy guzzler compared to this and for anything you want to battery power that's a big deal.