If i restore my iphone, will i be able to re-download my purchased apps for free?

Since i will be using the same apple ID

I think you can

Yes, you can. If you remember which apps you purchased, simply follow the same process you originally did to buy them, it will come up with the message "Are you sure you wish to buy this app?" (I something similar) and when you hit "yes" it'll say you already made this purchase and that you won't be charged again. There's a way you can find out what apps you've purchased but that are not on your device but I can't remember where to find that page off the top of my head.

Yeah you can alsong as you keep your same itunes account you can just redownload them all and don't have to repay. The only problem i found was that it doesn't tell you which you previously bought so if i was you i'd take note of which you have bought then you can refind them on the app store an get them that way, hope i helped.