Standard environment does not and it's a damn shame.
Flexible environment does not have that restriction.
But there is no free tier in flexible as far as I know.
Don't think there is, but for initial trial there is $300 credit for a year.
Free tiers are probably the least economically interesting aspect of cloud services. If you're using gae to do valuable work, you shouldn't mind paying a little bit for the service.
This is embarrassingly a Google-wide problem, not just a GAE problem.