What does Genesis 13:2 mean?

Even prior to the incident in Egypt, it was clear that Abram was wealthy (Genesis 12:5). Now we're told that he is very rich, specifically in livestock, silver, and gold. This is the first mention of Abram possessing gold and silver.

It is likely that Abram became much wealthier during his stay in Egypt. For one thing, Genesis 12:16 tells us that Pharaoh had treated Abram well and had given to him many animals, as well as human servants, when he took Sarai for his own wife. It is likely that Pharaoh allowed Abram to keep all he had given, and may have given him more, in light of his nearly-adulterous relationship with Sarai.

Pharaoh would have been motivated to appease Abram's God, as well as getting Abram out of the country, to end the plague on his household. So even though Abram failed to trust God, instead choosing to lie to protect himself, God was faithful to Abram in the end, both protecting and profiting him.