WElcome to the reloading world...you're gonna love it. First off, I don't know of any press that will load shotgun and rifle shells both. Someone on here correct me if I am wrong...I believe you will have to buy two individual and distinctly different types of loaders.
One of the very first things you will need is a good updated loading manual. Most all bullet and powder manufacturers offer them, but they are generally confined to the manufacturer's product for specs. I highly recommend getting the latest issue of the Lyman Reloading Handbook. I have the 48th edition, but I think I just saw where the 49th was issued. No matter, for your purposes, the 48th will serve fine. It is quite comprehensive in it's explaination of the reloading process, and gives detailed explaination of all the facets and reasons why. Really a great source book, and something no reloader should be without, in my opinion. It defines the process, and explains what additional equipment you will need.
At the top of the Reloading Forum, you will find a topic..."New to reloading? Read this first". An excellent breakdown of the essential items compiled by members of this forum, put together by mossy33oak.
As I said before, manuals published by product manufacturers are generic to their own brands for the most part. Hornady manuals will give loading specs for Hornady bullets, Nosler manuals for Nosler bullets, etc. Lyman gives specs for a wider range of applications, but does not cover them all, and you may find yourself needing specific info from brand-specific manuals too. Once you look at a couple of loading manuals, you will understand this better.
As far as brands and prices of loading presses, the door is wide open, and opinions vary greatly here. Personally, I load shotshells with a MEC press, and for the most part, use an RCBS Rockchucker press for rifle/handgun loading. I would advise you to buy equipment somewhere in the mid-range price spread until you see if you really like this stuff and may want to upgrade at a later date. I will say that nearly all of the better-known brand names are generally very well made, and should last for many years.
As far as cost goes, that's apretty wide-open area. Get some catalogs from such places as Midway, Midsouth, or any of the many other companies who specialize in this and get an idea of what you want. Powder, bullets, primers, cases, etc. can usually be bought at a local sporting goods store in your area that handles reloading supplies. The bigger catalog suppliers carry these items too, but you generally will pay shipping and other charges.
There are plenty of people on this forum who will be glad to help you with specific questions you will have. Don't be afraid to ask.
Hope this gave you some general insight into what you were looking for. Once again, I will say...get a GOOD loading manual very first thing......