Buy candles here.

Candle clocks are one of the ways that ancient people attempted to use natural phenomenon to keep accurate record of the time during the day. They consist of a long thin candle, which is marked at even intervals. When the candle is lit it burns down at a relatively steady pace, and by keeping track of which mark the flame is at, you can get a rough estimate of how much time has passed since it was lit.
As for the timer you can use any weight even coins.

You could even use incense and a ruler. Heck smokers do this all the time. A cigarette is about 5 min.