My website isn't generating any traffic yet as it's under developement and ready to be launch within a week. I need to sort out selling ads on my website's part as soon as I can. I tried to use Google Ad Manager but I cannot wait any longer to get approved via Google Adsense to review my application in order to get the "AdSense Publisher ID" to apply for Google Ad Manager? Do you know any nice interface website like Buysellads.com which you can do things like on Google Ad Manager without any requirement to have traffic on your site and also the function to approve what kind of ads you want to appear on your site one by one?
Google Ad Manager is an ad management system - which means that you would need to sell your own inventory and then enter it into the ad system. There are other management systems available like OpenX and Adzerk (my company). With these systems you would need to sell your own inventory though and traffic it through these systems.
If you are looking for someone else to sell your inventory for you then you should stick to AdSense or BuySellAds. There is no way around their requirement that you launch your site before using them - they need to know where the ads are going to be shown before they will approve you.
My suggestion would be to not worry about it right now - I would get your site launched and then worry about advertising. If you need something to fill in the space you can grab an affiliate banner from somewhere like Amazon.