If you plan to put Hemsedal on your calling card, only do so if you have a bank balance akin to that of Richard Branson. Put simply, Hemsedal is very expensive; however it is possible to do it on a budget, just watch the alcohol and taxis and the rest is surprisingly affordable. If you need to check your email then head for the Hemsedal Cafe in town, or the restaurant at the base near the Holvinheisen lift, and its free!
Hemsedal Cafe does a some good food at lunch, enormous portions.
Things kick off at the outside bar at the base where they'll often have live music from 4pm, then its after ski in the village. A beer will set you back at least UK£5, so hold on to it tightly. The main snowboard hang out for evening madness is the Hemsedal Cafe, which is expensive, cool, and full of gorgeous Norwegians. The skogstad hotel has a nightclub open late.
Accommodation can be had near the slopes, either at Veslestølen or Skarsnuten thats serviced by its own lift. The only trouble being that you're left with an expensive taxi if you want to get to/from the main town as buses to the resort finish early, but you can easily get quality apartment for a week for about £150 based on 8 sharing. Alternativley theres plenty of accomodation in town, or if the budget really tight then opt for a cabin or the campsite.