100% from a breeder - better price, and the snake will likely be less stressed, and more likely to be calmer and handle the transition to your home quicker and with less issues (such as poor shedding/ refusing food/ being prone to striking).
The stuff you'll need is pretty minimal and easy to find. A plastic tub is best for smaller/ younger snakes - nice and cheap/easy to find. You can use bigger ones as it grows for about a year, or more.
One day you'll want a 3ft. melamine enclosure or something similar - I made a 1m. long enclosure and it works well.
Paper towel as substrate is fine in the plastic tubs, I use recycled paper cat litter (breeders choice brand) in my melamine enc. for adult-ish sized snake.Hides can be those black plastic pot plant water dishes from bunnings, also dirt cheap, (get a few to rotate for easy cleaning, you'll want the smallest ones at first, the snake likes them not roomy, nice and snug in there..
You'll most importantly need a thermostat and heat mat. Inkbird thermostats work well, there are way better and more expensive ones though... Microclimate is super top of the line stuff.
hope this helps, I think that'll do for starters.