We go to Lagos quite a lot, in the past we have used a person called Alex who manages a bar in the town, very nice married man from Portugal, speaks good English, it was 60euro each way, if you want this I will contact him via mobile number and then pass the number onto you if ok to do this, which I am sure it will be as he is running this as a business advertised now in the bar.
On my next visit the hotel/b&b we are staying at offer this service so although 5euro more than Alex we are using the hotel's service just as we think it will be easier when staying there, I think this will be for people staying at hotel only, but again I would check for you if you would like this service.
Not sure what this price is like compared to the transport you were considering using, but we find this quick and Alex always there at the airport waiting for you and turns up on time to collect for the return journey, you are in resort in approx. 45 - 50 mins from Airport. Hope this helps,