There are a lot of options from various makers. One thought I had is a flashing red, or led light that clips on. I know in many Walmarts they have these in the sports section for joggers/runners, and bicycle riders. As far as just plain flashlight styles Walmart also has some really bright lights in the flashlight section that are not super expensive. Streamlight as was mentioned makes a nice light. I have, and use several Streamlights in the 200 lumen range that have taken a serious beating, and still work There is no need to go with a super expensive over rated light that eats batteries.
This is one of the down falls of many of these small yet mega bright so called tactical lights--they are bright--real bright, but have a run time of less than an hour, or so. Stick with a light that uses "AAA", or "AA" batteries instead of lights using CR123A's, and maybe even look at a light that could be recharged.
Another light that comes to mind that isn't super expensive is the "Big Larry" lights--not super expensive, and the have a mode that flashes red that is pretty bright. Like I said the sky is the limit because there are so many lights on the market today.