Can't speak for all the resorts,but,certainly all the main beaches in Lagos have concession areas, usually close to beach bars,where you can hire loungers and sunshades.The locals,however,tend to bring their own parasols and chairs with them.

I agree with Sagres..... anywhere I have ever been does have an area where you can hire beds/sunshades.
Where are you going to?
Pat

Thanks for your help didnt fancy sitting on the hard sand.

We are looking at either Alvor or Praia da Rocha up to now.

Do you know how much they charge roughly?

Think it was €5pp per day last year( mounts up when there's two of you and you're there for 23 days);in fact,come to think of it,we didn't pay that much for our flights !!
If you're going towards the end of the season,some places will let you have the loungers for nothing as long as you patronize their bar.