I've had cats all my life, and now home foster for a Cat charity (not RSPCA), with some indoors and outdoors in a run. No need to spend a lot, cats change their minds quite often on where they will sleep etc.
The first thing they need when they arrive is a "safe room". A quiet room just for them, if there is a bed they can hide under, great. Windows shut of course, but if possible, a window sill where they can sit and look out, or somewhere else high. If not, create some hidey holes, behind curtains, furniture etc, so they can hide up and gradual venture forth when they feel safe.
A cardboard box with a fleece or old cosy jumper to sleep, tucked away so they feel safe at first. Have a cosy cover on the bed or a chair.
We now use an quite large under the bed clear storage box for the litter tray. It has higher sides, and is roomy, so they don't spread litter everywhere. Ask for whatever litter they used before, and add it to what you want to use, so they get used to it.
We supply a cardboard scratcher, £1.29 in home bargains. We put their food on a tray then on spare piece of vinyl lino, so we can easily pick the whole thing up and wash it. I'd feed what he is used to at first, to avoid tummy upsets. (probably Felix sachets or similar)
I wouldn't let him outdoors for at least 3 weeks, and maybe more, depends on the cat. I would sit in the room with him, just reading, having a coffee, talking to him a bit, so he get used to you. After a day, start leaving his room door open so he can explore the house, but run back to his safe place.
Don't worry if he hides up for the first few days. Don't try and grab him for a fuss. Let him come to you in his own time. Just talk softly and maybe offer some Dreamies or a game - feather or stick under newspaper works well.
Good luck, he is a lucky cat.