Which dies and how many????

Let's see.  You need a die set for each caliber.  They usually come in either a 2 die set or a 3 die set.  The included dies are the sizer/decapper  and bullet seater.   The 3 die set usually includes a neck sizer/ decapper. 

Most companies don't include a shellholder in the set.  You won't need a shellholder for each caliber.  Some fit many calibers, it just depends on the size of the case rim.  For instance my Redding #1 shellholder works for 270, 308 and 22-250.  

There are a lot of fancy dies that have different sized neck bushings, micrometer knobs on top, and so forth.  I've never tried any of those, and have had good luck from the regular sets.  

I really like the Redding 2 die sets.  Well made, easy to use, and not that expensive.  

I highly recommend RCBS dies, life-time warranty.  I'd suggest a scale and a Lyman 55 powder measure.  You only need check every 5th or 10th dropped charge, and maintain a constant height in the powder tube to get good accuracy.

A thought.  Not everyone likes to reload, like golf and other things.  Why not buy one set of RCBS dies and the related shell holder.  Buy the die set for the rifle you shoot the most.  Start reloading and shooting that cartridge to see if you like it, and to get the experience.  You can always buy the other cartridge dies later?

The 243, 338 and the 270 are easy to reload for, the 7mm and the 300 Ultra are not difficult either.  But starting with the 243 will let you develop a varmint load, a target load and a deer load.  A pretty good start.

If you buy the kit, you should get a manual....READ THE MANUAL COMPLETELY.  Trust the manual more than friends if there is a conflict in directions.  There is a lot of bad advise floating around.  As on this board if you don't understand something.  If some one here gives you bad/dangerous advise you will immediately see a herd of flamers attack the poor advise and get right.  This is a big advantage from a jury system that is provided on this board.

BEAR

the 7 rem, 338 win, and 300 ultra are going to require the use of extruded powders, which do not meter well at all, therefore giving you inconsistent charge weights. strongly advise you to get a trickler, too, as they are only $10 or so, and will save you lots of headache. you may also get some good use out of the rcbs hand-primer - but that is not a must-purchase.

handloaded ammo is far and away better than factory garbage, if the handloader takes the time to make it so. meaning, you will spend a little time doing nothing but experimenting w/ many, or even all, of the variables that make up accuracy and velocity.

this is going to mean that your start-up costs are going to be pretty high as you weed thru the various components that don't work well. all powders are not equal even if they have extremely close burn rates.

the good news... once you get your load established, it is a simple process to duplicate it, and crank out hundreds or even thousands of the same load - meaning you won't have change anything until your rifle's throats start burning out, or you become dissatisfied w/ the load. keep good, detailed notes for each rifle, and you should have no trouble accomplishing your objectives. but, you won't save money for awhile - the start-up costs, the bullet and powder experimentation will probably actually cost you more money for the first year, maybe 2. after that, you will reap the economic advantages.

Lets assume that somehow you miss a powder charge.  It happens.  A client shoots the squib load and the bullet moves 2 inches into the barrel.  In the excitement of the hunt, he/she loads another round thinking they didn't' put the 1st cartridge in.  BANG.  Bad news for the client.

IF you had the same accident with factories, you would have no liability.  If you were sued (and you are right you would be) they would be going after the manufacture (deep pockets) and you would not pay a dime.

Lots of liability for minimum savings!

BEAR

PS I'd still recommend RCBS