Sauvignon I felt the same about Casino offers too and avoided them. I've recently dipped my toe in and been pleasantly surprised.
Start off by looking for risk free or no deposit bonuses or spins to get the hang of them. Most have such ridiculous wagering requirements that you'll bust out but if you're not playing with your own money you just as well give it a bash.
Recent good casino new account offers I've done are:
Playojo-deposit £50 and get 50 free spins. I put the £50 in, made £5.27 profit from them then withdrew £55.27 10 minutes later, no WR.
Ladbrokes-play £100 (min deposit £10) and get a £30 bonus. I was nervous with this one as you use your own money but it was simple, just repetitive. I deposited £20 in Ladbrokes casino. Used Starburst slot and did 10 lots of 100x10p spins (so 1000 spins total but you can use auto play). Balance after that was £27 so £7 up. Got the £30 bonus and used the same 10p starburst to wager it...just once I think it was. Finished off £47 up in total.