Cognito Forms currently offers unlimited forms, fields, entries and storage. As we stated from the beginning, we plan to eventually enforce a limit of 500 entries per month and 100MB of storage on our free plan.
We are releasing our paid plans and multi-user support for larger organizations this month. When we do, we will gradually begin enforcing both the entry and storage limits. You can find our pricing on our Idea Board, including feedback from our customers.
For your specific needs, our $10 Pro plan includes 1GB of storage and 2000 entries per month, so would be your best bet. For now though, everything is free except payment forms, where we charge just 1% of transactions.