Cheapest/smallest device to use and log to Strava?

I use Strava to log my trail runs and really like it. Currently, I use my phone and keep in my pocket, but there are 2 cons: the phone is bulky and the battery life sucks.

What is the cheapest/favourite way of logging to Strava that users can think of? How are you logging your runs?

I am sorry, I don't use Strava. I use a Garmin 310 XT and love it. It syncs with my computer, but so far I haven't used the info on there too much. My husband uses his, though.