Prayer candles? Votive candles?
The light just symbolizes your prayer.
It’s a symbol. The lit candle is the visual symbol of the prayer that’s in your head.
I can put in a dollar, light a candle and walk away, and nothing will happen, because I didn’t pray. I just went through a motion.
I can stay kneeling in a pew and pour my heart and soul out for someone, and it can be an okay prayer, even if I never strike a match.
So the candle doesn’t do anything to add oomph to your prayer-- everything that’s important comes from within.
If you want to keep your dollar, you don’t need to light a candle.
But if it makes you happy to see the little flickering light, even after you’ve moved your mind on to other things-- then yeah, light a candle and be happy. The money you spend is to pay for the candle you burn, and to help them buy more candles in the future.