1) A better jack (the one included with the car is kinda crappy). $23
2) A funnel that lets me measure just how much I'm about to put in. Around $5-8? Well worth the cost, I think.
3) Oil pan to catch the used oil. Includes lid and spout for easy emptying later. $5-6.
The filter was only $5. 5 quart Mobil 1 5W-30 was $20-something?
Followed the instructions here: http://john1701a.com/prius/prius-oilchange_iconic.htm
Didn't use a Filter Wrench. Getting it off required rubber bands for extra grip, but that wasn't too bad. Although I'm worried it might not be tight enough - I couldn't quite reach the recommended 3/4 turn after it hit the edge. Maybe closer to 5/8.
Didn't use a stand - ended up using the 1.5 ton jack on one side and the prius jack on the other side as backup, with a 2x4 and a 1x4 under the front wheel.