Daze and attack spells.

[isel]

If my mage is daze and make an attack spell and rolls least of 7 for the daze check, Do i lost the mana for the spell?

[Arkdeniz]

If you are Dazed you need to roll 7+ in order to successfully make the attack.

If you do roll 7 or more, you spend the mana for the attack spell and roll your attack dice.

If you roll 6 or less, you spend the mana for the attack spell but do not get to roll your attack dice.

For this reason it is often best to do something else with your mage if it is Dazed.

[Obsidian Soul]

I agree.  If you need to attack that turn, yoh should take a full action doing a non-attack action and then use a quickcast to cast an attack spell.

[Zuberi]

Follow the steps.

1. Declare Spell
2. Pay Costs (here is where you pay for the spell)
3. Counter Spell
4. Resolve Spell (here is where an attack is generated leading to the attack steps)

1. Declare Attack
2. Pay Costs (you've already paid for the spell, but if something makes you pay for the attack, such as a Suppression Cloak, then you must pay that cost now).
3. Roll to Miss (here is where you resolve the Daze condition)
etc

Remember that a crucial key rule in Mage Wars is that nothing is ever retroactive. You can not ever affect the past. Thus, if you simply follow the steps, it will help you figure out questions like this. Since the Daze is resolved after costs have been paid, it is incapable of affecting the cost. You've already paid by that point and that's that.