Target has hanging jars in their dollar bin! Only $1 each! (A small simple jar with hanging loop in clear or some colors. I think blue or green?) Create inexpensive outdoor lighting decor or even use them inside. Hang them in a grouping for a big effect—in a row or in a grid of 9 or 12.
Also, you can buy these smart tea lights for outdoor use, if you don't want to mess with a real flame and changing out candles every night. I believe you press down on them to turn them off and on. They don't look real, so use them up high or set them inside a frosted jar if that bothers you. I've also seen them available at HomeGoods for as little as $4.99.
Or if you don't want to do ANY work (no off/on switch), check out the Sun Jar. Captured inside the jar are a highly efficient solar cell rechargeable battery and low energy LED lamps. When the jar is placed in sunlight the solar cell creates an electrical current that charges the battery over a few hours. This energy is then used at night to power the three LED lamps inside the jar.