I would like to play around with iota transactions without putting real value tokens at risk.
Is there any zero-value iota test network?
You can use the IOTA testnet, simply by connecting your application to a public testnet node. It is designed to be lighter and quicker than the IOTA mainnet (transactions are confirmed more quickly), but parallel to the mainnet in almost all other respects. IOTA developers and community members will be happy to give you free test iotas to use; see the linked resource for instructions on how to get started.