You should use A1 taxis as they are the most less expensive and use the meter. I would think maybe around 30 le, I use the small buses going to Dahar, they are about 1 and half le, very safe no hassle. Get A1 number from the Internet, I have an apartment out in Ahayaa, you won't be sorry using them, the orange and blue taxis will try to rip you off.

It should cost around 20 EGP but no more than 40 one way. But before choosing a taxi, try to find a bus that goes past Makadi bay where your hotel is located as it is reasonably cheaper than taxi. In Dahar you will see many mini-buses or vans on the road, usually Toyota vans, which are very flexible and usually don't have any scheduled routes at all. You can stop them anywhere by road just by waving and ask the driver where he drives. For one ride you will have to pay 1.50 EGP per person. Another option is to find a bus to Marsa Alam which will wait at Dahar for some time before it leaves the city. The ticket to Makadi Bay on such bus should not cost more than 2 EGP per person and you can leave the bus when you think you are close to the hotel anywhere on its route as there are no stations. So think again if you really want to use taxi.