1. You can buy the Tiva Launchpad direct from TI for $13 including international shipping. That's what I paid to get it to the UK as Farnell was out of stock, it arrived via DHL in a couple of days from NL.
2. You shouldn't have a problem finding LEDs/resistors and other sundries. You can substitute a rotary pot for the slide pot if you struggle to get one.
3. The LCD can be bought from eBay from the various Chinese/HK sellers for under $3. It'll take a long time to get to you, budget at least a month, but given that the display part of the course isn't likely to be in the first few weeks there's no harm in waiting.
There are usually local sellers where you can buy and get it sooner for a little premium, but it's still cheaper than SparkFun.