Well first off let me just tell you that the markup on video games and electronics are very slim do to the amount of competition and chain stores such as BestBuy, Circuit City, etc...
But, don't let that get you down. Now if your serious about opening a video game store, you will need quite a few things.
First off, you will need to aquire a resellers certificate and a tax I.D from the government. This allows you to buy from distributors without paying any tax.
The next step after getting these documents is to contact the distributors. Now there are quite a few, but the two biggest and best known ones for video games are D&H and Ingram Micro.
After you have set up an account with your distributors, it is time to buy. The secret to making a reasonable profit from this industry and in the electronics industry in general is buying in large quantities. For example if you buy only 1 or 2 games from them, it's only going to be 3 or 4 dollars less then what you would pay at retail, which is not worth it.
In order to get good pricing you would need to order atleast 10 units per item and atleast 10 to 15 different items. This way you will be able to make a little return for yourself.
Now in your case, your saying you want to open a fresh new store. In order to be successful your going to have to stock this store with all the latest and best video games including Xbox 360, Playstation 2, Nintendo Gamecube and DS, Sony PSP, and the upcoming Nintendo Wii and Playstation 3. Your first order from the distributors should be between $50,000 to $60,000 dollars. If you do it this way, they will surely give you true wholesale pricing, probably $10 to $15 dollars less then the retail price for each video game and $50 to $80 dollars off the actual consoles.
I hope this helps, I know how tough it can be starting a new business. I used to own a video game store and now I have just started a computer electronics store. Best Wishes and I hope you do well, don't give up.