Candles are used in spells as 'spirit' of to take the spell up into the realm of deity. They are used to signify the element fire too. BUT they are not needed at all. The most important thing in the spell is your intent.
You could try using a statue as your focal point or just use coloured paper to act as candles.
I love to do simple spells such as a knot spell or Witches Ladder and you don't need a candle for that. Use your imagination.