There are many ways ammo is sold, from loose round bulk packs to carefully places styrofoam/plastic trays. Pretty typical stuff, but not exact easy to transport or reload into magazines quickly. Thumbing in each loose round is time consuming and painful. Not to mention if a box accidentally opens, all your ammo could get dumped in the dirt. But don't worry there is a solution!
First, there is some supplies you should look into getting: Loose Ammo, Stripper Clips, Stripper Clip Guide, Cloth Bandoleer, Magazines, Ammo Can, Mag Pouch, Ammo Pouch

If you take the loose ammo you can slide rounds into one of the ends of the stripper clips, typically most clips hold 10 rounds. With AR clips, you'll need to carefully bend the small tab up to keep the ammo from falling out.
With your ammo put onto clips you can put the clips in cloth bandoleers for easy transportation. Or you can put the clips into an ammo can for long term storage. Or even better, clips into bandoleer, and then bandoleer into ammo can.
When it's time to load your magazines, you'll need to attach the Stripper Clip Guide to the magazine, and then put your clip inside the guide. Push the rounds (but not the clip) down into the magazine. This is typically referred to as "charging" the mag. Make sure to remove the clip and guide once the mag is fully loaded. From there Magazines can be stored in ammo cans for long term storage, or in mag pouches for immediate access.
And here comes some extra Tactical Tuesday Tips! Imagine you've blown through all your mags. I sure hope you brought an extra bandoleer of ammo! If you did it's easy to quickly load your mags once again. This will save you time (money) when you're at a private pay-by-the-hour range. If you're out in the field, it will your weapon back up and firing quicker too. Another tip for those out in the field. Many people avoid bandoleers because they tend to bounce around, slapping the ribs, rattling and making noise. However, if you have an Ammo Pouch, like a SAW Pouch, or M60 Ammo Pouch, you can pack the bandoleers into those pouches just like you would a ammo can. The added bonus is that they are not as heavy or awkward as an ammo can.
Following the above techniques of Ammo RePacking you can: Have ammo readily available for emergencies (ie Bug-Out), prevent accidental ammo spillages, carry more ammo easier, quickly reload your weapon, prevent a reloader's thumb, and just generally look like a serious bad ass.
