Working best at a desk that is next to a window, these solar lamps contain rechargeable batteries that are juiced from the rays of the sun. The lamps last for about 4 hours, which should be enough for most purposes though it wouldn’t hurt if it lasted a bit longer. It takes about 9-12 hours for a full charge – allocate about 15 hours for a cloudy day. They’re not available for purchase online though, so head down to your local IKEA store to pick up one of these for $19.99 each.