Working as a freelance writer guarantees a steady stream of press releases in my inbox, and while the majority of them are off target or just plain useless, occasionally a truly exciting opportunity comes my way. The latest example was an offer for a $100 credit for Instacart, a grocery delivery service that recently launched in San Diego. I’d previously used a $20 credit to stock up on Cool Haus ice cream sandwiches and found the service convenient, so obviously I said yes. This time around, I gave myself a noble challenge: use the $100 to procure the ultimate selection of snacks.