We have a huge bucket for which we have setup lifecycle rules to archive data to Glacier. Now we have decided that we do not need the data in that bucket and hence want to delete all the data stored in Glacier as well as s3. If i delete the bucket from s3, would we incur a glacier cost for retrieval of data or would the delete's be free? The bucket has TB's of data and we definitely dont want to pay AWS 1000's of $ in retrieval costs
You can't delete a bucket that is not empty, so you'll need to delete everything stored in the bucket, including what's stored in Glacier, first.
If everything in Glacier was migrated to the glacier storage class over 3 months ago, then you should not incur any charges.
If you don't restore the Glacier objects -- you just delete them -- then the only charge will be for anything that as been in Glacier for less than 3 months. Deleting these objects will incur the documented pro-rated charge for early deletions, which is equivalent to the charge for storing the content in Glacier for 3 months, less the charge already incurred for the storage of the objects in Glacier.