Anyone try those generic Surface wall chargers on Ebay and/or Amazon? They have some for $0.99 and up. I am looking for a backup travel charger for my SP2 and from what I've read, the Surface charger should work (I know it won't be a quick charge if any but as long as I can run it plugged in it should be fine for my needs). $40 for a geniune one is just too much...