Yes, shoop.de is defintely good, I've already saved a packet of money through it. For us travellers, all the major hotels, airlines and OTAs are there. But I've also ordered flowers on it and bought a lawnmower. There's a huge number of online shops, like at TopCashBack.

Bregenz? Lovely place, I worked at the opera festival a couple of years ago. If you're there, you can try the shortest scheduled international flight in the world: ACH-FDH, all of 8 minutes with People's Viennaline!