I agree with moxy
I have used aliant powders for some time now and unique is very versitle and works well. I personally prefer bullseye for my pistol loads most times. I would recomend buying a pound of each and see what you like the best. I typically use gold dot HP for all loading too. I figgure I should practice with what I intend to use in the field. Most gun shops will order any powder you want if they like your money.
As far as a good place to find your non explosive components, I always recomend cheaper than dirt. I've been doing business with them for 10+ yrs now and dont have a single bad thing to say about them. When the unfortunate does happen the customer service department is the best of any company I've ever delt with.
I hope this helps you out. Remember to be patient s a new loader too. Take the time to enjoy it and the pride of a flawless match grade round made by your own hand. Learn from those before you. Those loading data books arent just sugestions. Take them as gossiple untill you have a few years under your belt. Most of all stay safe and pass on the knowlege to the next generation of shooters headed our way.