We got our two (brother Weasley and sister Luna, 12 weeks old now) 3 weeks ago from a rescue. They were really well socialized and definitely ready for their forever home. We're still learning but here's a few tips/things to get.
Bowls for food and water. We got some from poundland, those double type ones. Got a set for each of them though they usually share! We got them a blanket from poundland for in their carrier too which they've taken to snuggling into on the chair they've got in their room.
Speaking of "their" chair, we put a cushion in their carrier and left that open as a bed, but they've only gone in a few times. They prefer to curl up on their chair or on our laps. 
Cheap nappy sacks, baby wipes and a scoop are essential for cleaning up their litter trays. Use the litter they've been using to begin with. We've got a litter tray in their room and then one downstairs in the living room.
Keep them in one room to start with when you bring them home. When they start trying to follow you out, they're usually ready to explore the next room and so on. Ours were ready to explore everywhere within a day or two! They're really well socialised and adaptable, we've changed their litter and food already and they've been fine with everything
They stay in the spare room (their room!) in the day and come out at night once we're home from work. They've got toys and a scratching post in there along with food, water and a litter tray which they share.
Toys, we got them some cheap balls with bells in, a mouse, two dangly stick things and a cheap pop up tunnel. They really like scrunched up balls of a4 paper and cardboard tubes to chase after.
They'll playfight. A lot. I was worried they'd hurt each other, they properly go for it, but apparently as long as they're not bleeding they're fine! Don't encourage them to play with your hands/fingers. It may seem cute but you can get nasty cuts and scratches. If they try to play with your hands tell them "no" and move them away. They'll learn.
Oh and get them registered with a vet and get them neutered/spayed as soon as they're ready.
Enjoy! They'll take over your life, in a great way! 