Is there a way to continue using Bluemix for free after the free trial?

http://www.ibm.com/developerworks/jp/bluemix/credit.html

After reading this, if you register your credit card, you will be assigned a free quota, and you can use it for free within that quota.
If you don't want to register, you can't use it anymore.

At the end of the above URL, there is a description that all apps will be deleted after 60 days after the end of the free trial, so please make a decision as soon as possible.

http://dotnsf.blog.jp/archives/1005257489.html

If you look at this blog, you will find a trial calculation of how much it can be used in the free 375GB-Hour per month, so please refer to it.

If a month is 30 days, there are 720 hours in a month.If you use a 1GB memory machine for a month in a row, you will use 720 hours/GB.This will exceed the free limit (375).
But (default) **512MB memory machine can fit for free since it's 360 hours/GB even if you use it for a month in a row (1 month = 31 days calculation is barely OK).**In other words, the runtime of the application server is within the free frame for continuing to use one default 512MB memory server.
Or, calculations suggest that you can continue to use two 256MB memory servers in a free frame.Well, I don't know if the application server will work properly at 256MB...