So this question has been on my mind lately: if I bought 100 dollars worth of bitcoin but a week later when I wanted to buy some popsicles, the price of bitcoin dropped 30 bucks. Would the vendor prices reflect this drop or am I taking a loss on my delicious popsicles?
The vendor prices are pegged to USD, the markets take an average of the BTC price several times an hour and adjust the bitcoin prices accordingly. That is why most people try to buy bitcoins only when they want to make a purchase and buy ~10% more than they need to cover any price drop in the short period between the bitcoin purchase and the bitcoins arriving at the market.