Before you prestige make sure you unlock the attachments to the weapon(s) you do well with. As long as you don't select the refund coin option (just the add additional slot) you can permanently unlock that weapon with all the attachments w/o leveling up again. It makes it very easy to level back up again.
But it looks to me you don't get that much coin the second time around. The 1st play through I think I was able to unlock nearly all the streaks with my attachments on most of the weapons and still had around 8 coins to go before going prestige.
weapon attachments don't require tokens to be unlocked. they automatically unlock as you progress through the 'weapon levels'.
i'm on my first prestige, going to use my 1 permanent unlock token on the Flak Jacket perk. i just can't play without it.