the first time i hit my summer setup i only had 1 pair of skis, so i got a beater pair of 195cm 70mm waist single tippers and it worked fine, i broke the tails so they were angled upwards, but then i bought a pair of good movement joysticks + a really bad pair of rossignol scratches for 100$, the rossis are now my urban/backyard ski and the movements are my everyday ride...
so i suggest you just look out for a old used pair of twintips and wreck them....
look in the B/S/T forum if you can find a good deal in your region....