I think it depends on the size you are looking for. If you want a good cheap option, I'd go with this one:
http://amzn.to/2B8QeU9 It's only $12 with free shipping, I mean you can't beat that.
Best one I found with strobe and 4 different modes was this option:
http://amzn.to/2zWwDsm . I'm always a little leary when it doesn't mention the lumens but it's all 5 star reviews, nothing less, so I'd think it's worth a shot at $27.
Let me know if you are looking for any more details