Welcome, my name is XXXXX XXXXX I will do my best to help you with your issueOk, first I would avoid a battery powered saw which is what the Ryobi seems to be from your description
You're likely to get a better quality used saw for the same money that you would spend on a new saw.
You can't cut porcelain tile with a manual cutter, you need a wet saw
How heavy is a used saw? do I need a table or any extra equipment like a air compressor.
A manual cutter is only for soft bodied tile
No air compressor, a work stand is beneficial. if the saw doesn't come with one then a folding stand/workbench like a Black & Decker workmate is a good option
So mainly I should invest in a decent used wet saw, a nipper, score tool for the backer is enough to start.
If you eventually plan on tiling a decent sized floor then you should look for a good a decent quality pro type saw (used)
Next is there an all purpose blade that I should get?
Yes any decent all purpose diamond blade will work fine
You also need setting and grouting tools
Great! Thanks. Oh yes. I forgot about the grouting tools. Is metal or plastic best?
to grout you need a good sponge an d a rubber float
you don't need the float for a real small job
When I do a transition strip on the floor, how do I make sure a wood strip does not break?
it won't break if it sits flat on the floor and is properly secured
Thanks. I'm ready to go to work!