Sous-vide method is foolproof and I have done it many many times. 1 hour at 60 degrees (or 56, but rare duck is an acquired taste), then take it out of the bag and put on a non-stick pan without fat, skin side down. Brown and crisp up the skin and render some fat and it's ready. For cheap sous-vide method, look here: Cook Your Meat in a Beer Cooler: The World's Best (and Cheapest) Sous-Vide Hack | Serious Eats
Alternatively, just put it in a cold pan with no fat, bring to heat and fry for about 10 minutes, then put for 5-10 minutes in a hot oven, still skin down. It should be a little bit pink. Easy. I would not skip the frying-from-cold step. The skin might come out soggy and you do not want that.