Personally I would not recommend second hand, or you could soon be faced with the need to replace the battery; (expensive!). This is very often the first thing to deteriorate.
Could you give some idea of you budget, and if you intend playing games.
OnePlus 5T review: Hands-on
Illustrator Andrés Lozano on his improv line work, brazen use of colours & hand sketching
iPhone X review
Comment envoyer gratuitement des gros fichiers ?