Waaaay too many variables in play here to be able to provide any kind of estimate. The single most expensive bit will be outfitting a bathroom; if the bathroom is still above your sewer line then it'll be a bit cheaper, but still it won't be a low-buck option. You're out close to $1000 just buying fixtures, before you've turned the first screwdriver.
Come back with more information and we can talk particulars. Or, once you've assembled those facts for yourself, you'll be able to do the estimating yourself.
No one can answer that b/c you didn't give details on size of the room, quality of the materials you wish to buy, & location. The cost of materials greatly vary depending on where you buy them.
Your biggest problem is going to be getting in drain lines for sinks, shower, and toilet. You are going to have to cut the cement floor and run drain pipes to all of the fixtures along with vent pipes.
I have an unfinished basement and we want to rent it out so how much would it cost to add a bathroom and just finish it, carpet, walls, insulation, etc? Thanks.
