Hello Helen. As you are looking to sell your property, then going for the most cost-effective decking makes the best sense. That being said, if on your next project you are looking for something with longevity, then I'd say it's definitely worth considering the range of composite decking products out there. They have great benefits over wood: slip- and algae-resistant to name but two. Here's one we made earlier!

Timber decking requires maintenance and these days people don’t have time to maintain things. Composite and cost effective.

I have decking and staining does make it look better and prevents it being slippery when wet, however, the last time I bought decking I had instructions not to stain it for 6 months therefore it may not be an option for you.

A dark grey stain/paint would look far more expensive than it is and will help preserve the deck for some time.