You are going to have to render it in order to get it looking realistic. You could add a photo texture of an actual bag in SketchUp but it’s still going to look a little rough around the edges.
What’s your budget for this? Render software starts at ‘free and easy’ to mighty’ expensive and difficult’ but of course more powerful.
Maybe try with Kerkythea as it’s free before looking at something like Twilight or Podium. (<£150)
If you want better results then you can look further at Thea or Vray. (<£1000)
If you want to graduate to Pro tools then that’s a minefield depending on what you are trying to do but they get very expensive very quick. (+£1000).