I know of a good free web host and they have been online for over 2yrs now, so they are reliable and they have excellent support, but believe me, they will not give you even more than 500Mb, leav aside 5Gb.

5Gb = 5000 Mb and it is ALOT
People usually look for that much bandwidth but even that is alot if you are starting up and its a new site.

Just re-evaluate your needs.

I am not saying you won't get it. There are some kids who will give you even 10Gb space, but then i often don't find them next month.

Choice is yours.