Go immediately to you local library and get a copy of "The ABC's of Reloading" (or bookstore or gunstore or Amazon.com, whatever).
Some of your original questions will be answered there and more questions will come up (and be answered) in your reading.
To answer your original questions:
Dillon, Lyman, RCBS are they basically the same?
Yes. Cast iron or aluminum presses, work the brass all the same. Do the same job
No. Customer service varies. Design varies in detail (e.g. some presses allow changing to left-handed operation)
Don't leave out Forster, Hornady or Lee Precision.
Should I start with .45acp or 45-70Govt?
Largely depends on you. Either cartridge is fairly easy to load, and to learn reloading with. If you want to carefully tailor loads, the 45-70, since you basically shoot those one at a time.
Do I need another safe to lock up power and primers?
I don't lock any of my stuff in a safe (but my Alaska state laws don't require it, either). But I keep all powder in their original containers and NEVER (thank you "The Rifleman") in any pressure-tight container. Smokeless powder burns fast (technically, is "Flammable" material), but does not explode like black powder does. B.P. is classified as "Explosive". However, if contained inside a strong container, smokeless powder burns VERY fast, and is tantamount to an explosion when the container finally does let go.
Is there a kit that will give me most of the beginning equipment I need at a reasonable price?
Yes, but keep in mind that every kit you find was assembled by someone else. There will be things in there that you will not find useful and things you will want will be left out. You will get up and running with less forethought, faster and cheaper with a kit, but ultimately will spend just as much money "tuning" your loading bench to your personal style within a year (my prediction). Question: Do you want to buy your stereo system already set up with all components or do you want to buy your stereo with just the "right" CD, Tuner, Amp, Speakers, etc.?
Kit, No Kit, both approaches are good. Which is better for you depends on you.
Last question what is a reasonable price?
I started a thread wherein I described a "Budget Beginner's Loading Bench You Will Never Outgrow" that lets you get started with the minimum amount of gear (but all first-class gear, nothing you will ever want to replace) to reload which you can add to as you discover your personal style of reloading. Of course, the applicability of the advice in that thread depends on you being somewhat in my class of shooting. I am a hobbyist, in it for the fun and to stay practiced in case of a defensive shooting situation. I am no 1,000 round a week shooter or bench-rest 1,000 yard match shooter.
Having said that, let me share with you some posts and threads I think you will enjoy, (after you have gotten your hands on "The ABC's of Reloading"). So get a large mug of coffee, tea, hot chocolate, whatever you keep on hand when you read and think and read through these.
The "sticky" thread at the top of TheFiringLine's reloading forum is good, entitled, "For the New Reloader: Equipment Basics -- READ THIS FIRST " For the New Reloader: Equipment Basics -- READ THIS FIRST - TheFiringLine Forums
The "sticky" thread at the top of TheHighRoad.com's reloading forum is good, entitled, "For the New Reloader: Thinking about Reloading; Equipment Basics -- READ THIS FIRST" For the New Reloader: Thinking about Reloading; Equipment Basics -- READ THIS FIRST - THR
"Budget Beginning bench you will never outgrow for the novice handloader". This was informed by my recent (July 2010) repopulation of my loading bench. It is what I would have done 35 years ago if I had known then what I know now. Budget Beginning Bench you will never outgrow, for the novice handloader.
Thread entitled "Newby needs help." Newby needs help. - TheFiringLine Forums
My post 11 is entitled "Here's my reloading setup, which I think you might want to model" November 21, 2010)
My post 13 is "10 Advices for the novice handloader" November 21, 2010)
The first draft of my "10 Advices..." is on page 2 of this thread, about halfway down. RugerForum.com :: View topic - Interested in reloading
Minimalist minimal RugerForum.com :: View topic - Lee Classic Loader Kit How much to start reloading....dirt cheap! - TheFiringLine Forums
or if the links do not work, paste these into your browser
(posts are #11 and #13)
Minimalist minimal (the seventh post down)
Good luck. Always wear eye protection, especially when working with primers and don't pinch your fingers in your press. Be safe. Always, all ways.