My dh and I had been shopping a few times together and walked past jewellery shops- and I'd pointed out some I'd liked- but not with the intention of him buying any of them.
After 5 months together/ after meeting, DH suprised me and proposed- with the perfect ring that he had chosen all on his own. The size was right too- he had taken one of my rings off my finger and had placed it on his pinky for a finger size comparisson- and remembered exactly where it sat on his finger!

My friend on the other hand is in a long distance relationship and was proposed to over the phone- she went out and bought her own ring!