If bitcoin didnt have market value before July 2010, what does this mean?
That means there were no exchanges or any other sort of marketplaces needed to form the price.
How could people buy it if it didnt have any market value then other than p2p, otc, and mining?
It simply worked on p2p principle- someone made an add saying "I am buying/selling xyz amount of bitcoin for xyz price" and then people responded accordingly and negotiated the price.