Let's share Mercado prices. I prefer to shop at the supermarket because the prices are fixed but for freshness and just a wider variety, a mercado is tops.
These prices are from Mercado Inaquito off of Amazonas and on Juan Jose Villalengua.
Leg of Lamb $4.50 a pound
Sea Bass (Corvina) Steak $6.00 lb
Avocados 3 huge ones for $1
Strawberries (Huge size) $1.50 lb (smaller are cheaper)
White Potatoes $2 for 2 kilograms
I didn't haggle.