I just beat the game yesterday and I started over again.  When I got to drebin I saw that I could buy the bandana and stealth camo.  The thing is I shot my way through the first time and I thought these items were for completing the game with no alerts and no kills.

Every guide I have read online says the same thing, what do you guys think and is the bandana or camo worth the 5 million or 2.5 million at the end of the game?

You can get them doing no alert/no kill too.
The bandana is pretty much useless in my view as you can buy ammos anytime you want.
But the stealth camo rocks, especially to get some of the painfull emblems ( like the Assassin one for Altair disguise).

My advice would be :

- if you want them fast and are not planning to ever go for Big Boss Emblem do a liquid easy game and go for no alert/no kill.

- If you're planning to go for Big Boss Emblem, you will get those as a reward when you get your Big Boss Emblem too. ( if you go for this I can't emphasize enough how the solar gun makes the Big Boss Emblem run so much easier !( the middle east disguise helps a tonn too). So continue your current run and get the solar gun in that one and you can go for Big Boss Emblem later on...

PS : Hard part of the Big Boss Emblem run is the motorcycle chase in Act3, the solar gun makes it a lot easier due to its high fire rate.( I had problems in Act 1 with Merryl and the frogs too but mainly because Merryl kept moving in front of me and I kept stunning her with the solar gun and then she would get one-shot by the frogs..). The solar gun makes Vamp real easy too ( whole fight took me 5 seconds..)

Neither is worth it. Camo makes you invisible to regular enemies Gekkos and bosses can still see you. The enemies can still hear your steps and if you set off and alert they can see you.

The Bandana gives you unlimited ammos but unless you are fighting bosses not worth it.

I would say if you want buy the stealth camo.