Being fairly new to rifle reloading myself, I'd suggest you buy components in smallish quantities until you know what works best in your rifle. 100 bullets at a time will give you enough to do some load testing, if you like the results you can always buy more. 50 might not be enough. Luckily, varmint bullets are relatively inexpensive.
Same thing with primers and powder. A pound of powder will load 175 rounds at 40 grains per round, that should be enough to determine if it's what you want to stay with or not. Over time you'll end up with half a pound of this, half a pound of that. That's fine, since it gives you some choice to pick from when you change components or even rifles. 7.5 pounds of a powder that didn't work well for you is a different situation, since you could have tried several different powders for what you paid for the 8 pounder.
If you know anyone that will loan you a Hornady manual for a few days, you can check out the pages pertaining to 22-250.
The Nosler Ballistic Tip Varmint bullets shoot well for me, prices are similar to Hornady. Their reloading manual is available online free of charge.
The Hodgdon website has some good information, although whether they use the same bullet you have is hit or miss.
You'll probably want a chronograph at some point, to correlate what you expect to see with what you're actually getting for velocity. Then you can plug your actual results into a ballistics calculator to determine bullet drop at range "X".
The same powder charge, same primer, etc in two different brands of brass MAY give you significantly different velocity. Without a chrony it's hard to see that difference without extensive range testing at longer ranges. The difference between 3000 and 3200 fps isn't much at 100 yards, but at 500 yds it's substantial.