PricePlunge offers two LED Window Candles w/ Color Changing Bulbs, model no. CL-99, for $3.99. Coupon code "SANDCENT1" cuts it to $3.79. With $1.99 for shipping, that's the lowest total price we could find for this quantity by $3, excluding the mention below. Each one changes from red to blue to green to purple, measures 8.5"H x 2.25", and requires two AA batteries (not included).
Note, you can also buy four for $5.69 or buy eight for $8.54 using the same code as above.
A close price: Nothing But Savings via Newegg has it for $5.99 with free shipping.