I am sorry, but how can DynamoDB be cheaper when I have to pay to provision capacity and SimpleDB is practically free for low-volume stuff like this? S3 is probably an even better option, which seem to be on the roadmap, thankfully.
DynamoDB is quite inexpensive at low usage levels. The Free Tier gives you:
"25 GB of Storage, 25 Units of Read Capacity and 25 Units of Write Capacity – Enough to handle up to 200M requests per month"
Both DynamoDB and SimpleDB have free tiers. credstash can happily live in the free tier until you are using it A LOT (more than 25 fetches/second, sustained). Storage in SimpleDB costs about as much per GB as DDB, but DDB gives you more free storage, so DDB is cheaper for any amount of data over 1 GB.
