Any wood workers here?

OK, I know I'm probably gonna sound like a dill for this, but here goes.
I have just put some laminate timber flooring into my study. I need to cover the expansion gap along the edge of the walls, so I bought some 19mm quarter round.
I painted the quarter round and thought tonight would be a good time to fit it, however, I didn't really think about how the hell you butt this shit together when you get to the corner.
Does anyone know how to cut this stuff so that it joins up properly at the corner? I don't have a mitre box and can't see the point in buying one just for this.
Should I just take the lengths to Bunnings and get them to cut it?
I have just put some laminate timber flooring into my study. I need to cover the expansion gap along the edge of the walls, so I bought some 19mm quarter round.
I painted the quarter round and thought tonight would be a good time to fit it, however, I didn't really think about how the hell you butt this shit together when you get to the corner.
Does anyone know how to cut this stuff so that it joins up properly at the corner? I don't have a mitre box and can't see the point in buying one just for this.
Should I just take the lengths to Bunnings and get them to cut it?