In may your best options for skiing are in the mountains along the west coast, as well as Northern Norway, where it is often possible to do ski trips through the summer.Hurrungane (around Turtagrø), Strynefjellet, Sunnmørsalpene often have good conditions for spring skiing. Not so familiar with places closer to Drammen, but someone else might have suggestions.Stryn is good for lift served summer skiing aswell, opening around end of may, so you should look out for that.Getting skis cheap should not be a problem, since there will probably be end-of-season sales. The cheapest option might be to order from some webshop to an address in copenhagen though.