Cheap watches that can beep every 15 minutes?

Could you suggest some? I'm having trouble remembering to do RCs and I would like to do them frequently as well. It would be nice to just wear a watch that beeps every 15 minutes and do RCs at each beep, because I can wear the watch almost anywhere.

30 minutes would suffice also.

Thanks in advance :)

Is the repeatable countdown timer (which seems to be the same as a single interval timer) a common feature? I believe it's in the entry-level Timex watches but I'm unsure.

If you know of any non-super-fitness watches that can beep every 15/30 minutes let me know.