There is not much limitation at free version. You can enjoy completly without any restriction.

Only some features are deducted.

Such as:

• Cannot add flash movie cards (swf).
• Cannot send to multiple users.
• Cannot send card on schedule date.
• Ecard Random module not included.
• User cannot upload own image to create cards.
• Navigation

Check details list at http://www.odude.com/home/odude-ecard.html