Here's where you can find the free version of How to Brew:
http://www.howtobrew.com/
Also check you tube for how to brew videos, and look through the Basic Brewing audio/video podcasts.
I've been brewing for years and I use a 7.5 gallon pot, I also have a 15 gallon pot, but I mostly brew smaller batches, so I seldom get it out. You need to consider what your heat source. If you are using a kitchen stove, some are more powerful than others. My old Kenmore smooth top range can boil 6.5 gallons, while my G/F's Jenn-Aire can only boil about 2 gallons.
For brewing larger batches you need to get a propane burner, an electric brew system or run multiple batches on your stove.
I can brew 5 gallon batches on my stove top, but to avoid watching the pot for boil-overs, I use a second, smaller 3 gallon side pot at the beginning of the brew and then combine the 2 pots after about 20 minutes.
I use plastic carboys for primary, but buckets are fine. I use glass for aging cider and wine, but am transitioning to just using 5 gallon kegs for that.
I would recommend this 8 gallon pot:
https://www.northernbrewer.com/collections/megapot-1-2/products/megapot-1-2-kettle-8-gal
They are having a sale this weekend.
You don't need a spigot or a thermometer built into the pot.
If you want to brew smaller batches, you can get a 16 or 20 Qt pot at Walmart.
Walmart also has food safe buckets for $2-3, just drill a hole in the lid for your stopper/airlock.
Depending on your budget, there are some really nice electric brewing options available these days, either 110 or 220V. If you have an electric dryer, you can plug a 220V system into that.
You basically need 9 things to get started:
Brew pot
Brew in a bag, (BIAB) bag
Brewing Thermometer
Hydrometer for measuring gravity
Big spoon or mash paddle to stir the mash
Bucket w/airlock or Carboy (you'll need a big funnel to dump the wort in)
Auto siphon for bottling or transfer to keg
Bottles
Capper & caps
Look on your local craigslist or Facebook marketplace for used stuff, there's usually something available. Like always, check prices, some people are trying to sell stuff for way more than what its really worth.
They've got the cheaper kit on sale for $99, don't know if you can take an extra 15% off that price, but its still pretty cheap for what you get:
https://www.northernbrewer.com/products/brew-share-enjoy-homebrew-starter-kit
It comes with an extract kit so you can start brewing the day it gets there.
Its really nice to have a brewing scale (about $20) to weigh your grain and hops.
There's nothing wrong with starting small, you can brew 1.5-2 gallon batches in a 16 qt pot, and see if you like the process without spending a lot of cash.
Avoid brewing IPA's when just starting out, oxygen exposure seems to affect hoppy beers more than other styles, so get some experience and kegging equipment before you go for that.