Long line trench coat

strawb_shortcake

My Son has decided he'd like a long trench coat, in beige (inspector gadget coat). He's seen one online for £130 but I prefer to buy from a shop, I've looked online but can't seem to see anything as a starting point. Any ideas on which shops to look in? 
He's hard enough to get to the shops so I need to have a picture to show him to get him out the door. I do think charity shops would be my best bet but not sure he'll go for that??