Candles are just tools, props that are often used within magick, often to put us in the right state of mind for ritual work, sometimes to work as representation. They aren't a requirement and you can tailor almost any spell to not use candles, and create your own without their use.
These additional items such as candles, herbs, tools, crystals, etc are additional extras, rather than requirements, the most important thing is your intention.
Candles are simply a focal point. Magick requires the building and channeling of energy and light and heat are ready forms of energy. Also the colors of the candles usually just have certain symbolism, ancient archtypal energy that reminds you of the end goal of your spell. So instead of candles, use something that corresponds to the goal and embodies the objective.
Hey. If you feel you really have to have a candle but don't actually have any, you can always either download the image of a candle burning on your cellphone, tablet, or PC or use visualization to see the candle you want burning in your mind.