If you're looking to save some money, bring food from home! You can bring in 6.6lbs of food/person into Iceland with some restrictions (I think no meat and cheese... but honestly customs didn't even bother weighing nor looking at what food we brought). I checked a small cooler in a box (no extra fee but even if it costs $25 that's a great savings!) We brought granola bars, nuts/dried berries, PB and Almond butter packets, crackers, and dehydrated foods (most places have a microwave but you will get the weirdest look asking for one!). It was awesome having a base supply of food and saved a lot of money and time. Most hotels had breakfast so we would load up in the morning!
Iceland is amazing... enjoy the midnight sun!