On a Budget?
Iceland is expensive. Be warned.
Book trips ahead, look into discount cards such as CITYCARD and try to cook for yourself instead of eating out.
Do not shop at the local mini supermarkets downtown, or if you do please be warned that they are very overpriced. Instead, opt for the larger chains such as Bonus (the logo is a big pink big) or Krona.
If you plan to drink, consider buying your alcohol at the airport in duty free.