There is no fee charged by Coinprism.
As part of the Bitcoin network, you may decide to include a "miners fee" (also called transaction fee) when sending Bitcoins/Colored Coins, which will speed the transaction. This fee is not mandatory and not charged by Coinprism.
You can basically create your own coin for free. Note that when you issue Colored Coins, you will need a very small amount of Bitcoins (called dust and equal to 600 Satoshis ~ $0.0024 in the current version of Bitcoin ) which is the minimum required in a Bitcoin transaction (this is why you would need to fund your address with at least 600 Satoshis). Note that you can uncolor your Colored Coins and recover this dust.